You can also encourage everyone at the table to follow guidelines established by improv practitioners; these become less "rules of the game" and more "rules of play" (i.e. they don't really answer "what can I do next" as much as they address "whatever I'm going to do next, how do I do it?"):
Accept every offer. During the course of play, other players will make suggestions about the ongoing narrative, sometimes directly involving your character. Accept what's offered; don't block their suggestions. Try, as much as possible not to say "no", literally, or figuratively. Don't say "no", say "yes".
Accept and build with new offers. During the course of player, when you have an opportunity for agreement, don't just agree (see first guideline). Take what's offered, and build on it with a return offer. There are two ways to do this: add detail, and add complication. Note that both of these help you steer around the natural reaction against the first guideline ("I don't want that!") to "get what you want" or "avoid what you don't want" for your character. Don't just say "yes", say "yes, and..." or "yes, but...".
Make simple offers. There are a bunch of other players at the table; just as with boardgames, play rolls along more smoothly when there's as little down-time as possible. Engaging the other players is key, so when you provide details, be simple, straightforward, and incremental and then throw the tempo to another player (or the referee). When you say "yes, and..." (or "yes, but...") say only one thing.
These are also commonly known as "No Blocking", "No Wimping", and "No Steamrolling".
For some more explanation about how these things work in improvisational theatre, check out the Improv 101 series of blog posts (I found them by googling "no blocking no wimping", so they were a fast find, not necessarily "the best" find -- lots of other improv resources exist). There are lots of ways in which improv doesn't map well to RPG gaming, but in a lot of ways, good advice there is good advice here.
Based on personal experience, I might suggest one that's gaming specific and in the spirit of the improv guidelines:
The game is a player. You can think of the game's rule engine itself as a player at the table: so, when it has offers (i.e. you use the rules to help adjudicate an outcome), don't block or wimp or steamroll its offers. As much as you possibly can, resist temptation to fudge the offers of the game itself; as much as you possibly can, try to play the game as written (before you decide some part of it is "clearly broken" or "not to your taste"). In Burning Wheel, terms, you can think of this as "Say yes, and roll the dice..." The dice can suck, but you must give them that freedom: it makes for memorable play experience.
Short answer: Yes, No and Yes.
"Do these aspects cover all the bases that Str, Con, Dex....etc do?"
I am answering this question as if it were "Do these attributes cover all the attributes that Dungeons and Dragons includes?"
They do, if you replace what the character prefers to do with what they can do. Using the sample attributes you have posted here, someone with high Charm would prefer to convince people to share his/hers point of view and/or distract them from the real point of a conversation. In Dungeons and Dragons however, someone with low Charisma is incapable of (or really rather bad at) convincing or verbally manipulating another. In the system you have posted it is clear that a character with high Charm prefers manipulating people, but it is unclear whether they are capable of (and how effective they are at) verbal manipulation. (I am assuming you originally wanted the system to represent skill over preference, and just worded your question in a different/wrong way, as preference is completely binary, while skill has a curve.)
The same goes for other attributes as well, I just used Charm as an example.
"Do they cover the bases that the WoD statline covers?"
I feel the only attributes in oWoD that are not reflected by yours are Appearance and Endurance. In your system, Charm and Heart reflect preferences on social approaching, while Appearance is, well, how beautiful your character is. Don't worry though, I always thought that Appearance was the most stupid attribute in the history of pen and paper RPG's ever, so don't include anything similar, I'd say.
Also, someone with high Brute seems to prefer direct, brute force approaches that might resolve a situation quicker, and that someone with high Finesse prefers a slow, but more delicate and careful resolution, but there is no attribute to reflect how long a character can keep trying to do physically taxing tasks (running, jumping, climbing, etc.)
Apart from these two oWoD attributes, I'd say all the rest are reflected well.
"Is a character with these as stats missing some functionality I can't think of?"
Apart from oWoD Endurance/ D&D Constitution, You have covered the majority of the ground that most popular pen and paper RPG's cover, as far as attributes go. However, as humans are very complex beings, there will always be aspects of the human mind, more so than the body, that play a vital role in social interaction and mental challenges and that will elude most people, or that are being passed off as too trivial by others. Examples include, but are not limited to:
Expression: Does Sam know what gestures to use when conversing to further his point? Can he control his microexpressions consciously while conversing? How good is he at using body language to get a point across?
High Expression: Sam knows that when Lord Downey asks him if he has any children, he should not blink when he says "no", otherwise Lord Downey might know he is lying and seek leverage by endagering his son.
Low Expression: Sam thinks that shaking his head vividly left and right when he says "no" in reply to Lord Downey asking him if he has children, will convince him that he hasn't.
Empathy: How good is Sam at noticing people's stances and gestures or microexpressions while conversing? How good is he at 'reading between the lines', meaning, how good is he at examining what people say and how they say it, to be able to uncover what they are truly thinking and feeling by what words they choose and how they say them?
High Empathy: Sam knows that Lord Downey is feeling righteous about trying to frame him with the packet of arsenic because the Lord answers with questions that try to make Sam admit he has often acted with the belief that his opinions are over the laws of the city.
Low Empathy: Sam isn't sure whether Lord Downey is feeling remorseful or righteous.
Critical Thought: How good is Sam at judging how he should deal with a situation to provide him with the result he will be most satisfied with?
High C.T.: Sam knows he will get more answers out of Lord Downey if he respects him as an enemy and if he threatens his position of power within the Assassins Guild.
Low C.T.: Sam thinks trying to appeal to Lord Downey's morals will bring out the good in him, making him confess.
Captain Sir Samuel Vimes Lord Downey
Notes to consider/Afterthoughts/Suggestions:
Make your attributes represent competence, more than preference.
Think about how much detail you want your system attributes to go into, before deciding what to include (example, does Charm include how good a character is at getting his point across and how good he is at sensing what the other people's motives and feelings are, or do you want the two to be separate attributes?)
Discern between knowledge , education and intelligence; The three are completely different. Knowledge is gained through education, but also from experience and perception. Intelligence is inherent from the minute someone is born, and cannot change through natural means. Perception is altogether different, but can be raised through training.
Good luck with your system and feel free to ask any other questions you may have! Have fun!
Best Answer
I'm going to take the contrarian point here:
If you're still designing elements for the game, a playtest is the wrong choice
See a much better written explanation here:
Now, as he explains, there are excellent reasons to playtest, mainly to test the comprehensibility of your rules.
However, when working out the game mechanics, you should have a complete statistical model of your game. You must not rely on other people to figure out that the mechanics of your game do not match the intent.
Instead, using graph theory and statistics and game theory, you should be able to completely model the mechanical-theoretical (and mechanical-practical) domains of your game. You, as game designer, need to prove that every given combination of elements fits your intent and the expected behaviour of players.
This restriction of "complete mathematical model" also has the nice side effect of reducing reliance on silly systems that obscure and obfuscate the stats behind the scene in some vain hope that it will make them go away.
Regarding:
This means that you aren't ready for a playtest. At all.
Instead, you should be using statistical models to look at all possible outcomes of the combat/skill check system and the modes of modification that feats introduce. Only when you believe that your statistical model is correct and complete (which by definition requires making all of the mechanical elements for that subsystem of your game) and rendered into some textual form, is it time to test.
You will be testing two things:
You should be able to predict the outcomes of the mechanical interactions that your playtesters attempt. (See: making your beliefs pay rent.) If the outcomes do not coincide with your models, try to investigate where your model was incorrect or your explanation of system was incorrect.
It is quite possible that you did not anticipate ranges of action being taken, and playtesting can show those.
The danger is Do not design your game for your playtesters. Instead, use them to identify flaws in your writing and your models of system.