No glaring weakness. You lack an ACE pitcher, but your SP is still solid.
Im actually sold on McLouth, so I think you are fine there. The biggest issue I see is that your 3rd outfileder and your utility player Justin Uptin and Maybin. Both are young prospects with some of upside, but they are also both young, unproven, and carry a lot of risk. Though they may contribute this year, most of their upside is long-term, which doesn't matter since this isnt a keeper league. There's a good chance at least one of them will have a good year, but I wouldn't count on both of them......I would at least try to get some extra insurance from the free agent market.
I would try to grab at least 1 more OF or utility player. The problem is I don't think you should trade anybody (Your starters are solid, but the bench players aren't good enough to have any trade value,....or to fill if you traded a starter). So scour the waiver wire for a OF/Util with upside.....but otherwise you have a solid team. Stewart, Andres and even LaRoche are all expendable.
If I had to pinpoint something, I would say you could use a pitcher. I never liked Felix much, he is so up and down,I dont trust him. As for Joba ,who knows, a lot of hype but we will see how he performs. Your offense clearly outdoes your pitching.