He's not dead! No one ever dies, plus he still needs to marry crystal and tell Wanda that she can't date a android. He'll be back by the end of civil war
I hate to break it to you, but he probably won't get back, unless Warner Bros magically loses all their copyrights to Quicksilver as a character. Marvel knew they were cutting it close, so they had him in for only the one movie.
Still....if we cry enough he could be back. After watching three days straight of Supernatural, I refuse to believe anyone on any movie is gone for good.
It can sound pretty wrong when it's written like the first..