Jab, cross, staight, hook, uppercut, elbows, knees, roundhouse, sidekick, front kick... Pretty sure those are TKD basics and they seem to be pretty common in MMA.
Gracie Jiu-Jitsu may be minimal, simple, and effective but that's not enough if the fight doesn't go to the ground. GJJ is not the MMA solution any more than any other style of martial art.
I'm tired of people not understanding there is a functional side to TKD and an artistic side. TKD is a martial art and any martial art requires adjustments to be an effictive fighting method.