Tornado I actually use very often, whenever there are adds around or really whenever there are multiple targets (not just at bosses). It already does more damage* than brutal strike on a single target and its threat gets increased. Of course it would have been nice to have an area attack that could hit more targets and it would have been nice to not have a three second cooldown on it, but it's better than nothing and I would actually keep it maxed if you have the points. (* Don't misunderstand me and think you should use tornado on single targets because the fact that it doesn't gain beast power means it actually loses out against single targets, but as soon as there's two and you're not worried about cutting down the numbers asap, then it's worth it)
So as to what to sacrifice, I agree I'd kick a point out of beast roar. I have it at rank 2 or 3 now, and while I do run into the cooldown, it's usually because my target refuses to switch to me and lower cooldown probably wouldn't help anyway.
As for keeping aggro without brutal strike... well, I'm not max level yet, I've only gotten to abandoned lab for tanking, but I'm often actually almost at triple the value of the next guy (meaning I do almost as much damage as the DPS does). Now granted, that's because they switch to the adds to get rid of them while I often keep hitting the boss (or using tornado) and because I'm probably better geared (I replaced my green pandora weapon by a +4 weapon with 2 +3 strength runes from the abandoned lab, and have most of the abandoned lab armor) so I'm not saying I'm outdamaging DPS classes... but it's a big difference, I can't see how a few pieces of equip would result in a 300% difference in threat, so I feel I'm pretty secure in maintaining threat
Your rotation while tanking is quite simple (I guess that's what you're asking with 4? the chain?). First off, wild crush whenever it's off cooldown because it's an awesome BP gainer (and you want to keep the DoT up). Rage smash is your default spam skill to do damage and gain BP. What you do with your BP depends on the situation. Generally I like to always gain BP up to nearly 100 because it gives you an emergency buffer. When you're almost full (80 or 90), if you're secure in surviving (the healer has you covered), use fury strike. If you need to supplement your healing, use cruel bite. If there are adds around, use tornado when available (usually just use two other skills in between tornado's, depending on what's off CD and how many BP you have).
For some fights you may want to save up your BP for certain events. For instance against Gedenhard I make sure I'm at 100BP when his summoners appear so I can help in taking them down ASAP. There may be other fights where you want to make sure your wild impact is on cooldown, though I havent found those yet and just use it whenever a large group appears and it's off CD.
Also, if you're not struggling to stay alive yourself, don't forget that survival is actually a party heal. If your partymembers are getting hammered, pop it, even if it doesn't heal them much, it may be the difference between them living or dying and perhaps the party wiping or succeeding.
For the stats, well, that's the statbuild I'm going for probably, but I don't know if it's the best... In the grand scheme of things though, your stats don't really matter that much. I do know however that vit has a higher impact for us grizzly's than for other classes because the HP you gain from it gets multiplied because of our bonuses. Also, our max HP doesn't only determine how much burst damage we can survive, it also directly affects our selfheals.