I've been through Naxx-25's Construct Quarter three times now (with 2 Thaddius kills), Military twice, and Spider, Plague, and FWL once. That's 100 individual loot items, including tokens but excluding trash drops. How many of the pieces I'm interested in have dropped?
None, of course. :P
What am I looking for? This, or this (or this for this, I like both, and they're both upgrades), or this. I'm sure there are other things that are small upgrades in there (like shoulders - I should probably look into shoulders), but those are the pieces I know I can't upgrade elsewhere (yet, anyway).
The bracers in particular I'm not satisfied with the 'equivalent' i-lvl items; I don't like the stat spreads. The 7.5 chest is another piece I don't like the stat spread for. I'd rather keep what I've got than take a piece that's really better for a different spec. Part of it is balancing hit rating - not dropping too low, and such. I would be okay with swapping gems out for crit or AP again if I got a piece with more hit rating, but so many of the potential 'upgrades' would drop my hit rating to the point I'd have to reenchant for it, which would probably result in a net crit or AP loss.