Their defense will be improved. Michael Young moving to third - with Omar Vizquel of all people replacing him at short - and Josh Hamilton potentially moving - with Andruw Jones of all people possibly replacing him - should make the pitchers look quite a bit better. Last year the Rangers defense combined for ~ -37 UZR while their pithing staff had a league leading .322 BABIP against.
Help is on the way. We don't do a ton of prospects coverage here, but maybe we should. If you haven't heard of Derek Holland, Neftali Feliz, Julio Borbon, Engel Beltre, Michael Main, Justin Smoak, or Elvis Andrus quite yet, well, you will. Obviously not all of them are guaranteed to work out, but it's never a bad thing when you align this much young talent.
Speaking of Feliz, here's a video of him warming up:
Neftali Feliz of the Frisco RoughRiders (Texas) (via farmsystem)