We haven't had any issue with Human Variants in our games, but if you find it is too much then grant something else as a variant instead. IMO the +1 to all stats is very meh. Or simply remove them, they are a variant rule after all.
FYI, in our games everyone starts level 1 with a feat, the human variant gets two. Granted the way we use multiclassing and other rules, our game is high-powered at lower levels, but this is intentional so new players can get the feel for more powerful features without having to wait until higher levels we might not actually even play to...