We return 5 of our top 7 WRs from last year (Collie and Pau'u only ones gone/not playing this year). Added experience and improvement will by itself lead to improvement there as collie and Pau'u weren't any better than any of those 5 that are returning. Romney in particular should take a huge step up as he played pretty much all of last season hurt and he appears to finally be healthy.
If there's any position group that is potentially weaker it would probably be LB, but even then we are pretty solid there.