Do you have any other idea how equipment could be obtained that would provide fun ?
Hmm, how about guns, that shoot random loot instead of bullets, when these bits of loot hit a target they do damage, but that loot is added to their inventory, or forcefully equipped. Shoot a guy in the face, an you might slap a suit of power armor on him, or stick a rocket launcher in his hands.
Sure as hell wouldn't make any sense, but it would be fun right?
Melee of course, wouldn't be affected by this, to retain its ridiculous power level in comparison to other weapons.
Yes this whole post was a joke
You are right grinding is not supposed to be fun by design, it is repetition at it's base.
I would say seriously though, that the fact you need such high levels of engineering to craft or upgrade armors deters a lot of people, along with the huge price difference, combined with the fact you can repair lower tier versions of armor much easier makes wearing them much less of a risk with usually only very little traded off negatively.
i.e. the actual physical differences in combat while wearing CA compared to CAmk3 might not outweigh or evenly match the cost offset, and the ability to craft such items may still be 5000 repairs or low level crafts away for other players.