They've definitely got better WR talent than a couple years ago, when Gates' only help was Vincent Jackson. Rivers is having a second straight great year so far, and if they can find a decent healthy RB to keep on the field their offense is as good and versatile as it should be with a respected former OC as head coach. It's defense that's been killing them for a while though, and I just don't think Flowers is a one-man defense. Last year they were the classic example of a team that blitzed a lot (and well) because they COULDN'T cover long; it'll be interesting to see how much that's still true.
The frustrating thing is it probably won't be tested much before WE test it, so there's no way to be sure how big a challenge awaits Manning and our WRs and TEs. I think we're "significantly" better at QB, WR offensive line and defense though, so I feel pretty good about the matchup as long as we do our job every down from kickoff to gun. It's just that, in terms of AFC competitors, SD looks more credible and complete than NE (brutalized more than one,) Cincy (brutalized by NE) or Indy (whose defense is as bad as ever and already lost to us once.)
The nice thing about the schedule is it looks like all last years AFC division champs (except maybe NE) will repeat, so we'll play and thus control own destiny against all challengers, including SD.