[RPG] Artificer Thunder gauntlets taunt effect

No. A few things to note that stand out

1. crafting bonuses at lv. 3. Being able to gain the equivalent of a current lv 10 ability for artificers at lv 3, even if only for one kind of object is overpowered. Being able to gain powerful armor so early in the game seems cool, and is, but it is way too powerful at such a low level.

2. too flexible. With all these available options at lv 5 and increasing, this gains too much flexibility for a subclass. Consider that one of the main properties of the warlock is the eldritch invocation, and that you have a similar amount of special abilities as invocations for the entire class, as one of the class's main features, and you can see that for a sublcass, this is way too good.

3. Lackluster higher abilities. I get that heavily armored is supposed to be it's main thing, and it's scaling is most of the subclass, but the higher abilities are so underwhelming that they almost might as well not exist. The sixth level thing is confusing, and better suited as part of the original ability, and martial weapon proficiency at lv 14? I don't want to harp too much, but that is way too late to be gaining proficiencies in weapon types. At that point your character should know what weapons they want to be using, not gaining proficiencies in all martial weapons.

4. Inbalances in the main feature. The main feature, as mentioned previously, is obviously the Heavily Armored ability. At level 17 you can use the majority of your subclass' ability into casting a cantrip as a bonus action, while at the same time at lv 12 you have protection from most mind manipulation, and at just lv 8 you can essentially be the ultimate underwater explorer. These are quite large differences, and the problem is that in the quest for diversity in options while retaining balance, most of these abilities come across as bland, and not particularly diverse at all.

5. Confusion with the main ability. The AP points don't make much sense to me. You start out by saying you spend them to enchant the armor, but then all the later abilities require using them (and not a small amount of them), but only at later points in time. You need to clarify if you need to save points, or if you can unenchant things later or what. Also, either way, the limit on how many you have versus how many you spend on later abilities makes them quite limited, when you generally just want to have cool enchanted armor

6. It's not all bad. I do like where you are going with this though, regardless of what I have just pointed out, and I don't want to feel like all I'm doing is shutting you down here. I'm not. I really like the idea. I really like the basis behind the main ability. I love the idea of an armor-enchanter. It just still needs work

All and all, I really like where these ideas are coming from, but it needs a lot of work. By trying to create diversity while retaining balance you seem to have achieved neither. So here's my advice.

1. Move the armor creation ability back. It's just too powerful for a lv 3 character to have

2. Move up martial weapon proficiency. At lv 14, people either have martial weapon proficiency, or they don't. And if they don't they've already built around that, so essentially the proficiency at this point is pointless.

3. Consolidate the armor enchantments. Instead of having so many different enchantments that don't get any job done that they are supposed to, make a few packages that get better as you level up. Like this:

Mind Protector (Requires 10 AP): You gain immunity against mind controlling effects created by spells of level 3 or lower. For every extra 2 AP spent on this enchantment, the spell level it protects against increases by 1.

Have a few sets like this, and you can have diversity, utility, and balance all in one, without being too much or too little of any.

4. Change the other AP abilities. The other AP abilities are just confusing with how AP works. Instead make them into enchantment sets of their own, or build them into every set, as I describe next

5. After this, you might need some more abilities. Not to worry. A good way to do this could be to have the abilities of each enchantment set get an enhancement. Perhaps have an ability added to each, that lets you de-level them in exchange for a temporary boost. Something like that. Or, create new abilities that just give all of your enchanted armor some bonuses. That would work as well

I really hope that all of this helps you. I can't wait to see how you change this for it's next version, and I hope that this helps gives you a feel for what needs changing in that next version.

Update regarding the Booming Blade errata (6/9/21)

The Booming Blade errata adds one change relevant to this answer: the weapon used as part of the melee attack must be worth at least 1 sp.

Regarding Thunder Gauntlets, the weapon for Booming Blade would be "your armored fist". So the question (for your DM, probably) is, how much is your armored fist worth?

If you verify your gauntlets/gloves are worth at least a silver, the original answer is still good.

Original answer below:

The description of the Booming Blade cantrip says (SCAG, p. 142; emphasis mine):

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails. On a hit, the target suffers the attack's normal effects, and it becomes sheathed in booming energy until the start of your next turn.

Yes, you can use Thunder Gauntlets as part of Booming Blade

This is because Booming Blade requires a melee attack with a weapon, and Thunder Gauntlets states:

Your armored fists each count as a simple melee weapon

Yes, you would get the debuff effect from Thunder Gauntlets

The spell effect states that the target takes the normal effects of the attack, which includes both the damage and the distracting pulse.