Rapid Shot is too good, but I think it's for different reasons.
IMO, Archers have it a bit too good to begin with, mainly because of how harsh close combat is in 3E, and because of the stacking of bow and arrow bonuses. On top of that, with Point Blank Shot and Rapid Shot they get a couple of the best combat-oriented feats in the core rules.
And Rapid Shot itself definitely has issues... Not because it's better than Weapon Focus - if we tried to nerf everything that's better then Weapon Focus we'd loose half of the combat feats. A feat with prerequisites should be better than a vanilla one like Weapon Focus.
The problem is how much better it is than Two Weapon Fighting: You don't have to worry about splitting your money to get a secondary weapon, you get to use the same damage die as with your primary weapon, you get the same damage bonus from strength, and all your feats increasing to hit probability, damage, and critical range will apply to your every attack. Unless the guy with TWF is happy using two shortswords, that's a huge advantage for the archer.