In Wrath of the Lich King, Blizzard is clearly committed to ditching the "master of none" part of Druids' "Jack of all trades" for good. In particular, regarding the topic at hand, they're trying to ensure that Feral druids can be either first-rate DPS or first-rate tanks (though not with the exact same spec). And Savage Roar, I suspect, will be a big part of bringing that first-rate DPS for kitty form:
Savage Roar (Rank 1)
25 Energy, 100 yd range
Requires Cat Form
Finishing move that increases attack power by 40%. Lasts longer per combo point:
1 point : 14 seconds
2 points: 19 seconds
3 points: 24 seconds
4 points: 29 seconds
5 points: 34 seconds
Remind you of anything? If you're at all familiar with Rogue PvE cycles, this looks very similar to Slice and Dice, which any serious rogue tries to keep up 100% of the time in a typical boss fight. The duration on Savage Roar is slightly more than on a fully improved SnD, which is nice. The spell is baseline and learned at level 75.
But how much will the +40% AP help us, aside from "a lot?" I'd say it's still too early to tell for sure. However, given the importance of AP to a cat's DPS, I strongly suspect this spell will find a way into our current Mangle/Shred/Rip cycles, transforming them into something closer to a combat rogue's 4s5r (build to four CP, SnD, build to five CP, Rupture). In fact, given that this spell starts with S, we may have a 4s5r of our own; but again, given different buff uptimes, energy regeneration differences, different buff effects, and so on, I'm going to leave it to the guys at Elitist Jerks to math it out.