I think I like the slated concepts pretty well overall. I've taken a little time to think about each of them, and I feel like sharing my immediate reactions to each.
Defective Ability--
I quite like this concept. I think this concept has several different, interesting ideas to explore. There's a fairly small set of negative abilities, but they're very different from each other, and I would be interested to explore most of them. Trying to manage the downsides, or even leverage upsides in a few cases is an idea that excites me. I do wonder a little bit about the power level. It's pretty inherently easy to make something that's too weighted down by some of these abilities, but I also worry a little that it would be easy to be tempted into overcompensating for them.
Game of Inches
This might be my favorite of the concepts on the slate. I think it would be interesting to explore a variety of gradual damaging or recovering effects. I think there's a lot of space to explore, and I think this is one of the more elegant, or flexible of the defensive concepts, in that it has a focus on what the pokemon does instead of trying to restrict what it cannot do. I feel that incremental recovery effects are an especially rarely used space, and it would be fun and novel to try to truly take advantage of them.
Limit Break
I think it is somewhat interesting to consider how to take advantage of being attacked by the opponent. I don't think there's quite as much space to consider here as for some of the other concepts, but it's a relatively rare thing to occur in mons, and it would still be interesting to work with. I think in particular it's interesting to consider the opponent's role in battle with this, where they might have some control over when and how this pokemon gets a boost. That feels like an exciting angle to consider.
Boxing Gloves
I can't say I feel especially excited by this concept. It would be interesting to explore how wallbreakers can compensate for their poor typing, but I fear this is just going to be a sort of high-statted pokemon that hits very hard. Maybe I'm not thinking of enough possibilities, but this just isn't one of my favorite concepts on the slate.
Hidden Potential
I think here I'm less concerned with the power level (although that is a concern), and more feel that the pool of results is not especially interesting. Pokemon with incredible coverage do exist, and can be balanced, but it's not exactly a design space that I feel interested in. Alternatively, if the pokemon winds up using only one multi-attack nearly all of the time, then the result is perhaps even less interesting to me. For example, if it winds up using using nearly only Multi-Attack Ice (just using an example type here), it's basically just like, Glacial Lance the pokemon, and it hasn't really explored multi-attack, but it still theoretically has the possibly problematic ability to blow past its checks with a different type of multi-attack. However, if it does use multiple attack types well, then that raises concerns about what reliably checks it, and how to effectively scout it. My reaction to this concept isn't fear, it's disinterest, which I think is worse.
Boosting and Blasting
I feel that this has an interesting similarity to Limit Break. If either B&B CAP or Limit Break CAP were to trade blows with an opponent, both concepts would get something out of it. However, I think that I'm more interested in Limit Break, which feels more novel to me. I'm also a little concerned about the power level here-- getting a boost while attacking is a strong effect, and I feeel that many of the best ways to showcase it are very high power as well.
Bulletproof Glass
I find this concept interesting. I think it's a difficult, yet fascinating task to make a good, useful bulkmon with relatively low defensive stats, although it has definitiely happened before. I feel like this would allow a huge amount of room to explore different possible defensive typings and abilities, which could be fun. I do worry a little that this could turn out overly metagame dependent. I think the most meta-game independent bulkmons are blanket checks that use high defensive stats and decent typings to check a wide range of pokemon. I think it's possible that this would wind up primarily targeting a handfull of attackers, and fall out of favor the moment those pokemon do. Still, I would like to explore this, and I think of it favorably overall. It just feels unusual that this is the main concept where I truly worry it could be underpowered in a slate with Defective Ability.