I find myself wondering if the issue is not with the talent itself, however, but with the itemization of all 2h weapons in the 60 - 70 game.
Remember Demonshear? Look at the speed. It's a 3.8 speed blue 2h sword, obviously tuned for MS warriors.
It didn't always have that speed. It was 2.3 speed when it first entered the game. I know because I used one in my iconoclastic fury 2h build that sacrificed big slam damage for rage generation. (I actually remember it as 2.2 speed, but the screenshot proves me wrong.) There wasn't a ton of hit on plate back then, the PvP epics had barely been introduced, BWL was still cutting edge and so it was still feasible to try and avoid rage starvation by the simple expedient of swinging more often. With Flurry up, Demonshear's 2.3 speed dropped to a satisfying 1.8 or so. This meant swings of a 2h weapon that approached the speed of a one hander.
Right now the only 2h weapons left with a speed that fast are the PvP polearms. You'll notice that, even among polearms, they maintain an anomalous 2.2 speed. Unfortunately, polearms aren't included in the Titan's Grip tooltip, and as such cannot be used with a Titan's Grip fury build as an offhand. Which is a damn shame, because I suspect a 2.2 or faster 2h weapon would go a long way towards minimizing rage starvation for a dual wielding warrior, especially in solid haste gear with Flurry up. An offhand swinging at about 1.l7 speed increases rage generation, increases your specials, and thus helps use the ability to its fullest. The only issue is, does the damage lost from Whirlwinds cost more than the rage generation gives? Does this adversely affect Slam damage? Since there's no way to test a 2.2 speed 2h weapon with Titan's Grip unless Polearms are included, this is beyond my ability to answer. (Also, I'm not in the beta.) The idea seems sound enough, though. (If I'm wrong, I'm wrong.)
It's a fair criticism of this idea to point out that it moves against what seems to be the prevailing trend of Wrath, which is to say trying to make more weapons accessible to more classes and specs. Fast 2h weapons would be, in this view, good for DW fury warriors and no one else. This is a fair criticism, and it may means that the fix for the talent will have to be in the talent itself rather than in itemization.
What I think we'll need to see is a return of fast 2h weapons for offhanding with Titan's Grip. I don't think the talent itself is broken, I think that the vast majority of 2h weapons are itemized for a different use than that which a Titan's Grip warrior will be putting his offhand to: they're not designed for rage generation, but rather for burst damage (from a warrior's perspective) since the main uses for a 2h in current play are PvP or as part of a slam rotation. Failing this itemization change, I'd have to say it makes more since to use Titan's Grip to main hand a 2h weapon for stats and high damage while offhanding a fast 1h weapon for rage gen. Even with the current amount of hit on gear (and with hit obviously going up as more hit rating will be needed at 80 to get the same results as we get now at 70) missing too often with two 4.0 or slower weapons seems like a death sentence. I can forsee a lot of weapon switching macros popping up.
Still, we've been promised more work on warriors in the beta, so hopefully this won't turn into another rage normalization kerfuffle. Either we need to see tweaks to the talent to make it rage friendlier, or we need to see gear fill in that gap.