Not enough characters have gone through that many iterations. Merman is more drastic though... Had a sex change, lost the flipper for legs, then lost the legs and then turned into a lamia.
MDR is developed for Star Trek Voyager Elite Force, a game developed on mostly late Pentium IIs @~450MHz range, so surely MDR is lean enough for that. The motivation for MDR were the memory savings and the allowing of a crapload of animation frames for believable single player drama, and using MD3 to do the same task would be unfeasible.
However, this doesn't mean OA will start supporting STVEF players. That would require cgame changes, to allow players2/, jpeg icons and worst of all, mp3 decoding for their sounds (MP3 is strongly undesirable). Supporting the MDR format doesn't mean these must be done.
OA doesn't need craploads of frames either - i'd be happy to just use MDR to exchange memory usage for CPU usage. I have been playing with extending animation though (torso running, jumping and aiming animations)