I have and have heard many opinions on how this movie could be made better, and a FX makeover would help.
This is one of the few examples I can think of where an effects upgrade might help. The Final Frontier
always felt out of place with the other TOS films, partially because the effects kinda throw you out of the "universe". It's not because they are bad (they are) but that they are inconsistent with the rest of the films.