QB: You're in excellent shape. If things play out ideally, Vick will play well early enough and you'll be able to use him with no regrets in week 4 when Cam has a bye. After that, you'll be able to shop him and turn him into some help elsewhere (see below).
RB: Great group. I like your top 2 a lot and am quite surprised Sproles was still on the board in what I assume was the third round. Nice pick up there. Mathews is a solid flex with high-RB2 upside. I love both Richardson and Vereen, the latter particularly in PPR leagues. Bell will provide value when he returns. Essentially, you have 6 guys who are startable as either RB or flex plays. Lot of opportunity to deal here, IMO.
WR: Your top 2 are awesome, but man are you thin! I like Givens' upside a lot and think he's got a great chance to break out this year, but to only have three receivers is risky. You have the ammo to trade away for a stud receiver, IMO, since I'd bet there are several teams in your league that are shakey at RB. If the guy who owns, say, Brandon Marshall/A.J. Green/Julio Jones is one of said teams, I think he would jump on a WR1 for Mathews and Richardson deal in a nanosecond. That would allow you to start a stud receiver at flex and not have to worry about which RB to roll with each week. Food for thought if you can swing it. I'd start shopping these deals yesterday.
TE: Gates is old and a shadow of his former self. I do like Cameron's upside, though, and think you may wind up starting him sooner rather than later (if you don't make a move). Here's where you can hopefully upgrade via Vick after Cam's bye. If you can ship Vick for a top-tier TE, either straight up or as a packag, you're in business. May be a bit tough in a 12-team league since QB is so deep, but if Vick performs well in the new Eagles offense he's going to be a hot commodity on which you should sell high.
Overall I think this is a very good team with the pieces in place to be a great team if you make a few moves. Definitely a playoff team regardless if guys stay healthy, but you could be flat-out dominant if you swing a deal or two.