I do this trade for a couple reasons. First, Peralta adds some pop to my lineup, which is an area where I can pick up points. His relatively poor batting average doesn't hurt me too badly, it's the overall strength of my roster. And while his deal is expiring, he's an IRL Cardinal, so I could bring him back at a 30% discount if I wanted.
Mostly I wanted Coulter though. While I don't think he sticks at catcher, I think his bat will end up playing anywhere (.280/.425/.535 with 11 bombs this year as a 20 year old in A ball), and as a Brewer homer, he's my favorite Brewers prospect.
Wong's cost control is hard to give up, but I think he ends up a better real-life player than fantasy one. And Moreland is a decent, affordable asset, but I already have a couple other 1B/DH types with Vic Martinez and Edwin Encarnacion.
I'm buying low on both Wong and Moreland. I agree that Wong will be better in real life than fantasy (and hopefully better than he's showing this year), but if he can hit .270+ with reasonable counting numbers and some speed he should be a decent MI option to help offset the loss of Carpenter's 2B eligibilty. I'm a bit of a Moreland apologist - I hope they figure out his ankle problems and he becomes a UTIL/depth option. I also love Coulters bat and the thought of him sticking at catcher is enticing, but next season I have a weakness at MI and hopefully this goes towards fixing it for the long term. Moving Peralta leaves me without a regular SS and is a final admission that I'm not in a position to compete for the wildcard this year - I wouldn't be looking to re-sign him.