There's probably nothing wrong with a 7 weight, but it's too middle-of-the-road for me. I use a 6 weight a LOT -- but by the time I'm wanting to throw some huge #4 poppers or heavy clousers (or whatever else I have) the 8 weight just does it more easily.
That said, a lot of folks disagree. Harry Murray (a local legend here) prefers a 7 weight for smallmouth.
BTW - an 8 or 9 weight probably wouldn't spook any sunfish out there, so long as you don't aim your forward cast directly down at the water
. My wife fishes an 8 weight all the time and catches more bluegill than she wants to catch.