Well now, here's an interesting thought to consider this weekend: Zemeny on Barthilas suggests that maybe it's time to do away with a gear mechanic that Blizzard has used since Diablo. He thinks that set bonuses deserve to be put out to pasture. He doesn't go into his reasoning much, but we can probably fill that in; not only do set bonuses tend to either be overpowered or too weak (as in, you usually need to have a specific set bonus to make or break a class), but they make gear choices uneven, usually leaving you to choose between an upgrade or a set bonus. Zemeny suggests we do away with the whole thing -- create one set bonus per tier, leaving upgrades for the gear itself, or just turn the set bonus into an extra gem or inscription slot and give us more power that way.
Ghostcrawler shows up in the thread and says that the game would be pretty boring if set bonuses weren't included -- I presume he means that you'd just upgrade your gear according to iLvl, and that would be that. He even says that he wishes the tiers varied more, but players really want to see "unambiguous upgrades" to their items. People need rewarding when they move up, so GC can't mix things up with the various bonuses as much as he might like.