No, the energy check is still client side. The only way to waste a 2T4 proc is to get one off an auto-attack between when you tell the server to powershift, and when the server responds.

For my M'uru set I tossed on what I'd normally use for Bloodboil (high dodge). From there I swapped in slots for +hit and expertise, I have around 80-100hit, 80expertise, and our WWS showed about 70% avoidance over a night of M'uru attempts. If you are not tanking Entropius you can use lower defense/resilience since the blood elves are only level 71, 2.2% to be at cap. I also don't worry about armor as much as avoidance/hit/expertise, around 30-32k armor I believe.

Hit items:
[Pepe's Shroud of Pacification] 25
[Band of the Abyssal Lord] 21
[Thunderheart Leggings] 27
[Belt of Deep Shadow] 18 (wtb T6 belt, I only used this one night for testing and seemed fine but most will probably just stick to Natural Power if no T6)
Along with a couple Pyrestones agi/hit for socket bonus.

Expertise:
[Thunderheart Treads] 20
[Collar of the Pit Lord] 29
[Shard of Contempt] 44


Note: I have on a max avoidance set in Armory, NOT a normal tanking set obviously so that isn't much help to look at right now.

Edit: For M'uru it also depends on what is expected of you and the strat used by your guild. If they expect you to get all 3 adds for your side I would go for a setup like I have listed. If you're sheeping a berserker or even two sheeps every wave then you can get by with your normal gear fine, without trying to tweak.

To add to what Astrylian said, threat also largely depends on what group you can get into. These days we occassionally run a second Enhancement Shaman on farm raids to gear him up, and he goes in the tank group. Unleashed Rage is huge for threat. But if you're in there with just a Resto Shaman (SoE/WF) and a Prot Warrior doing Commanding Shout (or being lazy with Shouts), well that's not as much fun.

BM Hunter groups are generally good for threat as well, 2 x FI and Resto Shaman's SoE/GoA is not a terrible place to be.

The two encounters you mentioned specifically have some special conditions. While Flame tanking, you'll be in FR gear, so threat stats are likely to be gimped. Personally, I offset that by getting the 2T6 bonus (Shoulders/Bracers) and using a DPS gemmed/enchanted S3 helm (lots of Hit Rating), so play around with what you can achieve threat wise while remaining crit immune and FR capped. Bloodboil is mostly fine when you've got a nice Rage income from the ticking debuffs, but right at the start (if you're not the first tank) you can get screwed by crap Rage generation from too many glancings, or not enough hits/crits, and then you're playing catchup. You can try eating a Cleave or two to help though.

As far as Brutallus goes, I'm the first tank and usually in a 2 x BM Hunter, 1 Survival, Resto Shaman (SoE/GoA) group. I don't pay attention to the rolling TPS value on Omen, since it fluctuates a lot, but I note down how much total threat I had when the other tank taunts after 3 slashes. With 3 Misdirects, Bloodlust after ~10 seconds and Drums, my best was ~78k threat, so about 2600 TPS (lots of crits in this as well, not many miss/dodge/parry). Mostly though, I average around 52-58k, 3 x Misdirects, Drums, but no Bloodlust, which is a much more reasonable ~1833 TPS.

edit: It obviously peters off after the first 30 second segment, but that's the most crucial bit, to give DPS enough of a lead to start letting loose. I'll note down total threat on our next kill to find average TPS, but I don't know if that'll be as relevant since we spend half the time DPSing in Cat form.

edit2: It'd be nice if someone could adapt coolyo's TPS calculator for Druids:
[Warrior] Sustained TPS / WWSed
Coolyo[dot]org

Yep that works fine, exactly what I was looking for. Thanks! Never seen it linked here before =x