The videos from Gazelle Automations made a point to reproduce what to me is a defining, period-specific, aspect of TAS: the audio. I don't just mean the TAS music, but the 'tinny' quality of the dialog recording. As an audio and music enthusiast (I wouldn't put myself quite at the level of 'audiophile though), this has always stood out to me just as much as the visual style of TAS. It sounds like a 1970s cartoon. It would stick out like a sore thumb to me if modern animation was put on top of that recorded dialog. I don't know how feasible it would be to reduce the tinny, canned quality of the dialog audio.
If they were to do some kind of new animated productions set in the TOS era, then visually I would like something along the lines of the DC animated movies of the last several years. Pretty good quality 2D animation. I think stuff like vehicles may sometimes be done with 3D animation and cel shading, but I'd have to go back and do some re-watching for specifics.
Since games have been brought into the discussion as well... the problem with making episodes out of games is that the story structure and writing for an interactive game is different than for a movie or TV episode that you watch non-interactively. Like you have a cut scene to start a quest, and then you spend half an hour to an hour doing the quest, and then you have another cut scene that lasts a few minutes to end the quest and maybe lead into the next one. The 'quest' part would need to be completely re-written into something that's engaging to watch instead of play. And that would require new dialog, which can't be done properly without the original actors available. Supposed sound-alikes never sound like the real thing to me. It's why I absolutely could never get into newer Looney Tunes revival cartoons.
Kor