Too often what would seem to be a nice idea does not get thought through enough and subsequently fails in execution. IMO there was nothing wrong with the idea of giving players a way to boost the resist caps on thier suits, even at the expense of a little defense chance. Idea = ok (even if not everyone will use it). However what we got from that idea was a completely fubar system to utilize it. Quite frankly I think they know it, and did it on purpose. They want the system to be as cumbersome as possible with the aim of keeping us logging in trying to collect 474347744687 refinement pieces so that we can eventually complete a full suit with +5 mods on each piece. The same thing goes for not making so much of the new content in the last 6 months unstackable. I call BS on the idea that the refinement components could not be made stackable if they had gone with a simpler system... so why make them complicated and unstackable? I think it is blatantly to create a need for more storage space, which they will sell you in the form of boosters or additional accounts.
Agreed - given the lower refinements aren't worth crap - they could have had 4 types of refinements - all invulnerable level and they stack and it would take you 5 invul refinements to do 1 armor piece. Done. 4 stackables to collect and no special versions for each type of armor.
This whole 'lets make 8 zillion versions so people will trade' is complete BS and a thinly veiled attempt to get people to want more storage.