Carmack is more of a game engine engineer than a game designer, as evidenced by the lacklustre design of id games after Romero left.
Doom (2016) was released after Carmack left, but it's one of the best shooters they've made.
Q3 is more minimalist, which makes competitive play more interesting. Q3 has also maintained a competitive scene to this day where UTs seems to have fizzled out.
UT99 had some fantastic level design. Facing Worlds, Phobos, HyperBlast, Deck 16, Coret, etc.