Hell, I'd rather have them ignore the third game in the "current" Trails trilogy and move onto Blue.
You should worry more about Trails of Blue.
Don't you mean Zero? Blue's the second one.
If it came down to it, I wouldn't be opposed to them bypassing 3rd myself. It has lots of nice fanservice for those who enjoyed the first two, and you'd be left not really knowing a whole lot about Kevin's character without it, but outside of that it's not really essential. SC ties up almost all of the story introduced in FC, and everything else aside, 3rd simply isn't as good as the two before. Would still be nice for people to have it, mind, but if it meant greater chances of seeing the Zero trilogy in English... That being said, I think there's every likelihood that the entire Zero trilogy will end up ported to Vita like the original trilogy was ported to the PSP. They've already announced a full voice version of Zero for the Vita, after all. So if the trilogy is bypassed for localisation, I don't think it'll be due to the PSP dying.
On the topic of the game: super excited. Both FC and SC are among my favourite games ever, and more Kiseki can only be a good thing! I really need to find more free time, though. I still haven't played either Zero or Ao, and both sit on my shelf giving me sad puppy dog eyes every time I walk by. :/