The major changes I noticed between the two editions are as follows:
Limits prevent characters from being overly min-maxed. Each of them is centered around an attribute that is typically dumped in normal characters; the most important attribute for the physical limit, for instance, is Strength, though other attributes weigh in they have the same impact as Strength does alone. This means that you can't build a "never gonna fight close quarters" build and just dump strength and expect to do well in other physical areas, encouraging a well-rounded thing.
Mystic adepts get a huge buff. I'm not exactly sure that this is a bad thing; they still can't astrally project, but they get the powers of both mages (other than astral) and phys-ads pretty nicely. Were they still using the BP system, this would be a flaw, and I'm not sure about allowing them as the third pick on your priority system, but I think the reason that people are upset is because they don't astrally project as much as they should when not a mystic adept.
The priority system really makes things a lot better. It prevents some of the worst cheesing during character creation (don't get me wrong-it's still possible, but you have to know what you're doing and make some sacrifices).
Combat's been changed rather heavily on the bookkeeping, but not so much the execution. The Accuracy limit keeps pistols from killing Great Dragons, which is a nice touch, but also discourages just dumping into the newly increased skills and maxing them out right away. It also makes smartlinks a more tangible advantage, as do laser sights. Armor is now a single rating for stun and physical, which makes it a lot easier for new players to understand, and, in my opinion, more realistic.
Hacking's a lot better. Mind you; the wireless thing contains some logic holes and gimmicks with the new benefits it gives stuff like cyberware or laser sights, but hackers can enjoy a target rich playground with new rules for hacking that make prepping a hacker 90% easier and playing one about 50% easier; GM'ing hacking also became a lot easier. In addition, some of the more broken technomancer stuff has been revised so you now have a reason to play a decker instead of a technomancer every single time.
All in all, it's faster and more streamlined. If you want my "reviewer" version, you can check it out on my blog, but I've said pretty much everything I said there here, only without the sales pitches.
Most of the retconning has occurred as the present, real-world timeline has overwritten the future-history timeline of SR.
E.g. as far as I can remember, the 1999 Seretech Decision didn't actually happen. (OR DID IT?!?!?!)
Keep in mind, the timeline of SR has advanced in the Core rulebook and in many of the various sourcebooks that come out - there's usually a metaplot event or two that becomes cannon. (E.g. the Arcology Shutdown)
Best Answer
Edge is valuable, powerful, and limited. It's also impossible to regain without the GM's discretion. The GM is supposed to give it back when the player does something cool or impressive. As a long-time SR GM, I advise you to only restore Edge when that cool or impressive action didn't require Edge to begin with.
Blitz is powerful, but Edge is supposed to be. It's actually less useful for Combat Mages than it may seem, because any combat mage worth the name should have Increase Reflexes (SR5, p. 288) on a Spell Sustaining Focus (SR5, p. 320).
A Sammy is likely to have Reaction Enhancers and Wired Reflexes (SR5, p. 455). In addition to extra Initiative Dice, these systems increase Reaction directly, providing a static bonus to the Initiative Attribute (SR5, p. 159).
Blitz only provides dice, and it doesn't stack with anything (it just pushes it straight to the cap). You ask if a point of Edge is "worth" 30 Initiative Score, but rolling 30 on 5d6 is unlikely. A roll of 16-19 represents 39% of the possible rolls. The chance of a 30 is significantly less than a full percentage point. (The direct bonuses don't have any effect on the probability of the dice, just the final result.)
Seeing as a character with cybernetic or magically enhanced Initiative is also going to have a higher Initiative Attribute before the dice are rolled, the effect of Blitz is somewhat less dramatic than you believe. Blitz is most effective on people who probably shouldn't be anywhere near combat anyway, like wage slaves.
Besides, it'll be nice every now and then, but unless the GM is excessively generous with Edge refresh, the players should always be thinking: "Is spending Edge on this really that important, or do I want to keep it to save my bacon later?"