The major problems with crafting gear for top performance is that other game content gets left out since "oh well this enemy doesn't drop an upgrade" idea comes into peoples minds so they tend not bother with any of that content. Which is the problem, like not ALL slots will get replaced but only allowing endgame gear to count for 2-3 of your gear slots out of EVERY PIECE is a terrible policy to follow.
Ajbs were a decent idea but imo if they allow that sort of thing it needs to be world NMs nothing inside of a raid. and it should at least balance things out a little since you need to go to endgame as well as as get crafted items, however don't forget that out of everyone that played FFXI very few people even got to see full sets of that stuff out of the entire population.
I do like the whole system of sky from FFXI some of my fondest memories of FFXI endgame were there and I won't argue against that concept and I do like it but at the same time we do need a lot more options to keep things fresh to help everyone tell the difference between FFXI endgame and FFXIV endgame. We can't just clone it.