Since the latest patch, i've had access to higher ilvl pieces of gear. My question is, when is breaking the T20 2/4 piece bonus worth the extra ilvls? I know haste is king, but is it more valuable than the set bonuses?
The tier set bonus values for Fury are actually quite high. Someone made a spreadsheet with this information. For example if you would want to break your 4 set the damage bonus of the higher Ilvl gear pieces should be more than 11% to make up for the bonus loss you get from breaking the 4 set. It can become a bit complicated. The best advice I could give you is to sim your gear using Raidbots. The spreadsheet will atleast give you an idea of how powerfull the set bonuses are.