Focus Fire is going to last 20 seconds instead of just 15 seconds. I would guess that the CD also becomes 20 seconds. Yes, a longer buff is nice. But it says one thing to me: BM hunters were blowing it as soon as it was available and not trying to get more stacks of Frenzy. So now BMs have more time for additional Frenzy stacks to pile up. When they get a large stack they should blow other CDs to multiply the effect. So yes, this is an easy buff, but in the right hands and care it could be used as a larger buff.
I've always felt there was more to be gained there. But I couldn't see how to squeeze it much more without adding a huge amount of complexity. This was greatly reinforced when Kripparrian said that he just macro'd them into all his shots when he did Heroic Rag in a BM spec. (So he just got whatever stacks he got every 15 seconds.) Of course that's about as top-line raid awareness as it gets, so over-complex application of abilities isn't that desirable.
T.N.T is going to proc much more of the time. It will go from a 12% chance to 20% chance. That's a beautiful thing for improving single target DPS.
It will fix the issue with just waiting and waiting for abilities to come off CD. And it might even help some of the focus starvation. It will certainly give SV hunters a little more to think about in balancing out their attacks and ensuring the DoTs keep being applied.