I was so excited to get into tier 5 content. All this new gear! Until I looked more closely at the lolerific Tier 5 set bonuses for feral druids.
2 pieces: When you shift out of Bear Form, Dire Bear Form, or Cat Form, your next Regrowth spell takes 2 fewer sec. to cast.
4 pieces: Your Shred ability deals an additional 75 damage, and your Lacerate ability does an additional 15 per application.
Contemplate that 2 piece bonus for a bear for a second. You're tanking FLK and he's hitting you for 3000, 5000 a hit. OMG you're about to die! Quick, pop out of bear form and cast an instant Regrowth! Uh huh. You'll get a 1000 point heal and then you'll be trapped in elf form with no armor for 1.5 seconds, where you'll take a 12,000 point hit and die. Right. It's an insultingly useless bonus for bears. And not much better for cats, since cat gear has no useful +heal. It's like this bonus was designed for some mythical druid that's simultaneously flinging heals, melee dps, and soaking damage. Maybe I can work a Starfire and some meleekin action in there, too. The 4 piece bonus on Tier 5 isn't much better, either.
So with such lousy set bonuses, is the T5 worth it for bears? My guildmate Karthis doesn't think so until you get 5/5. His analysis involves working out the stats in detail. Me, I'm lazy and am just going to compare tank points.
T4 T5 Diff
Head 780 895 115
Shoulders 634 727 93
Chest 927 971 44
Hands 559 654 95
Legs 757 905 148
4/5 Tier 4 150 - -150
Total 3807 4152 345
So what does this wall of numbers tell us? Measured in tank points, 5/5 Tier 5 is indeed better than 5/5 Tier 4. No surprise there. But I think Karthis is wrong about partial sets. Tank-point-wise, the T5 pants are so much better than the T4 pants that they're just about worth the upgrade even if you break the T4 set. And other than the chest, any two pieces of T5 combined will improve upon the T4 more than the cost of losing the T4 set bonus.
So by my analysis, the T5 is pretty well worth it. I suspect the difference in our conclusions comes mostly from how important we think that 1400 armor is. I'm simply taking Emmerald's tank points calculations at face value, but I don't understand the model behind them very well. The high-end mitigation lists value 1 stamina at about 40 bonus armor.
Keep in mind also that both our analyses only consider survival stats, not threat generation stats. All that extra strength and agility gives the T5 more threat. There's even some +hit thrown in! That's a nice thing to help you keep up with your T5 warlocks and mages.