...I'd guess that Quicksilver is going to be not much more than a throw-in for Days of Future Past; basically an appearance to stake a claim. I'll be surprised if he's a major character.
He's a throw-in pretty much everywhere. His dad is a supergenius and master of electromagnetism, one of the top two villains in all Marveldom; while his sister is so powerful she created her own alternate reality. Quicksilver is fast. Not Flash-fast, just fast.