Sanchez will be a free agent at the end of next season so it's hard to believe this'll be the sole addition to the rotation. I mean that wouldn't really make much sense unless Moore thought he could extend Sanchez or flip him at the deadline. What I suspect is happening is that front office believes the Central is up for grabs and wants to go for it but without mortgaging too much of the future.
Now Sanchez alone doesn't vault the Royals into contention so I think that a trade for another starting pitcher - one with a well established track record - is still a viable possibility. I'm speaking of course of the move we've all been expecting, the one where Moore parts with Wil Myers or Mike Montgomery. Acquiring Sanchez doesn't mean the search for an ace is over.
Cabrera being dealt opens up centerfield for Lorenzo Cain, a player with plus defense and plus speed. Cain has significantly more range than Cabrera so his addition to the lineup will help all the pitchers. I mentioned on twitter shortly after the trade was announced that I hope Yost leaves Alex Gordon in the leadoff spot as his insertion there was one of Yost's best moves. I even went so far as to predict the opening day lineup, which I'll share here too: