Oregon offense is basically spread + option run/pass. Success came heavily from reading the OLB/DE depending on 3-4, 4-3, 46, or 3-3-5. Doesn't require the QB to read defenses- which is why Dennis Dixon, Darren Thomas, and Jerimiah Masoli didn't have successful QB careers after college. Mariota is a bit different because he can actually read defenses. Although his Ducks offense didn't primarily operate off of reading defenses, he utilized that this past year in the playoffs- which was also his demise.
Baylor offense was spread + west coast + option run. No route tree for WRs (have a friend that played at BU), simply timing routes, complimented by a hell of a lot of screens. This success of this offense was built off of quick, let me be clear- quick passes, so we're talking 80s-90s sets. This is why many RG3 and Petty had/will have trouble adjusting because that 80s-90s game doesn't work at the NFL level. QB success is built off of reading the defense and climbing the pocket.
By gimmick I think dude is referring to reliance on the QB option, which Cam, RG3, Russell Wilson, Kaepernick, and now Mariota have relied on to open up the pass game. It's gimmick-y because using it can cause defenses to play the run which can lead huge yardage gains off of play action.