Having the ENT cast portray holographic representations of themselves in an Historical holo-novel for an actual, living character from another series is where the controversy really lies. Especially, as the only seeming justification for it is to offer some pretense that Trip's death might've been, false ... and untrue. As well, Riker and Deanna Troi were portrayed at an age that was far younger than the actors that played them, which made it all seem even more 'forced.'
Taken on its own terms, however, TATV is an entertaining diversion. There's nothing inherently wrong with it, as a form of escapism, outside of some failed logic. But every show has that. "Why didn't he just use his phaser?!!" "Oh! Then the show would've been over, right away." That sort of failing is in practically every episode of the franchise, it almost can't be helped -- though, I admit, it's irksome, at times. Also, I'm not fond of holodeck adventures, with their whole premise of "... it never (really) happened." It's like a "dream sequence" which is often a colossal waste of time.
Nevertheless, I am a fan of TATV. With Jonathan Frakes leading the journey, the final episode of -ENT- was in $afe hands.