Exactly. There's some pretty good feats with DEX pre-reqs, so you'll need that. Also, if you're going the light armor route to get extra damage, you'll need a high DEX mod. Lastly, every Fighter should have some points in CON or WIS to help out with either increased durability or better OA's (preferably a little in both). That's just a lot of stats to juggle for a human.
Additionally, Tempest Fighters and TWF Rangers only really use one At-Will 90% of the time, and that's Dual/Twin Strike. So with those builds, your third At-Will versatility doesn't help much. For any other Fighter though, you can pick the two that work best and then Brash Strike as your third, so they'll work out good.