Yeah I'm still a die hard fan of the stamina stacking. Diminishing returns has just contributed to this. Its just too useful to be sitting above 40k or more for Sarth +3, Malygos, low player achievements, etc. It really lets you pile on the aoe packs too cause you're not gonna die with a good druid healer as long as your max hp pool can survive the spikes.
With the new enchants going in they almost seem to be encouraging us even more to throw the stam on. 34k-35k unbuffed is quite possible next patch. It'll be interesting to see how hard they make stuff in Ulduar hit.
I've still got defense enchants on but only cause I don't have those Sarth legs. As soon as I get them they all change to armor/stam except for shield until they add the new shield stam enchant.
Avoidance is definitely a very nice thing for things hitting for 12k+ but there reaches a point where you are giving up so much from someplace else to gain the slightest bit of avoidance. The gear in the game currently lets us hit 55%-57%ish raw avoidance as warriors (57% as night elf) and as high as 66%ish if you are a night elf DK without a single avoidance gem. I just don't see the point in losing the health to add more on top of that especially considering all the crazy magic damage flying around (34k breath nukes -_-). They are giving healers insane throughput now, it is a completely different game. As long as your healers are overhealing regularly you will benefit tremendously from a larger hp pool.