Thompson isn't an SEC QB from what he's shown thus far (limited game action, spring and fall practice). He can do some things in the zone read running the ball though. If Shaw were to go down, SC is pretty screwed although McEvoy is the guy to watch (also the most likely starter in 2 years when Shaw leaves).
But the hope is that with the way Shaw improved passing the ball over the course of the season and theoretically will keep improving, SC won't have to rely on him running it 15 times a game and will actually have a legit passing game. Who knows what to expect with WR. Shaw does spread the ball around though (even to a fault this past year), so wouldn't be surprised if Buster Anderson is the leading receiver. But Ace and KJ Brent will probably be the two main WRs if I had to guess. Jerell Adams is Jared Cook 2.0 physically, so if he picks things up quickly, SC could be really dangerous in 2 TE sets.
As far as the east, UGA is heavy favorite imo. Good offense, and nasty on defense with a ridiculously easy schedule. The key for SC will be to not drop any of the games that should be wins ie Auburn/Kentucky type games of the last 2 seasons. If that happens, could see SC win 2 out of LSU/Ark/UGA and win the east.
Not sure what to expect out of Tenn. In theory passing game should be ridiculous, but who knows on D and in the run game. At this point, I'd expect SC and UGA to both be better overall (especially with SC getting Tenn in Columbia). Florida is a wild card: just too ridiculously talented to have a 3rd down year you'd think, but also don't really have any returning playmakers on offense. D will win them some games by itself and they could win the east if the offense surprisingly is good.