I think this is much easier for sets that are heavy on active clicks. For protection focused sets, where there are a lot of toggle/auto powers, it becomes much more difficult. You can skip attacks once your chain is fairly seamless, you can have enough control, even buffs/debuffs compete for your limited time.
In armor sets, nearly everything contributes towards more survivability, and very little has an opportunity cost in combat, so the only easy skips are situtational powers like T9s with crashes, or rezes or just flat out bad powers. More survivable is usually better, regardless of form, and it would be hard to balance the game around a power point of players being so survivable that they would rather lower their sustain for more pool powers. If it doesn't come at an opportunity cost in combat, why skip? Endurance has been tried, but this clearly frustrated players a lot and is usually eventually circumvented, leaving it just a set that is unpleasent to use without extensive planning. (Haven't played dark armor in like 2 decades, but that is the general experience I have heard)
I still like the idea of powers each having a bit of a niche so they feel unique, but I think armor sets are a particularly tough spot to balance power choices. In this instance, splitting the +HP does serve a purpose to lower the delta between dull pain and no dull pain so that perma-DP isn't as appealing a build goal. I think these changes make sense and I like the new regen... I do wish I had a good solution to make power choices in armor sets more dynamic though. I don't think making sets more full of situation choices, or making every set super clicky is a good design, but I don't see another way haha maybe if pool powers were much more enticing, that could draw people away, but that comes with its own problems.