I've only seen Blood and Fire of Star Trek Phase II, it was impressive how they managed to recreate the sets, costumes and feel of TOS but I also think they aped it too much, hardly anything was original, they even seemed to copy the acting style. The guy playing Kirk for example didn't really play Kirk, he played William Shatner playing Kirk. That's obviously intentional but I would have preferred if he had made the character his own.
The biggest problem I had with that episode was the script, I can see why it was rejected for TNG, it was awful. Hey, look at our gay guest stars, they're making out and want to get married and everyone is totally fine with it ... whoops, space slug AIDS! And the solution is to kill the infected, it's the only way to be sure.
I was offended by that and didn't even finish the episode.