Sounds like you have quite the staff a few quality pitchers that you could get 1 v 1 for Strasburg would be Matt Cain, Justin Verlander, Clayton Kershaw, and Jeff Weaver I'd say those four are pretty close with their performences I just traded James Shields, Jonathan Papelbon, and Rafael Betancourt for Strasburg so i hope he doesn't get hurt and cotinues to have a dominent 2nd half of the season. I feel like your staff is fine as is, I wouldn't make any changes but that's just me.
the only problem with strasburg is if they put him on an innings limit for the season. if that happens he can only be of help for so long. so with that in mind it might not be a bad idea to try and deal him. i agree that someone like cain, verlander, or many other legitimate aces would be good targets. i've been thinking of doing the same thing myself.