A more logical explanation is that TNG, DS9 and VOY are the problem. ENT is great as a TV show and prequel to TOS. When the harebrained attempt was made to reintroduce characters from outside of the TOS/ENT realm is where the episode failed.
So the other three series that came before Enterprise, that all reached 7 seasons and have their own fan following of each character/actor, is the problem?
You're going to blame the entire TNG/DS9/Voy era of cast/crew for Enterprise's failures because they pulled out Riker and Troi for the finale?
As far as I'm aware, many of the main issues so many had with Enterprise before it got canceled was that there was absolutely no tie-in to the rest of the saga (TOS/TNG/DS9/Voy) so they tried to tie it all in by using the Borg earlier in "Regeneration" and then again in the finale, they used Riker and Troi from TNG, who were part of the larger, more instrumental actions of making the NX-01 & crew exist in the first place (First Contact)...... and now it's all their fault that Enterprise, while by your claims was great as a tv show and prequel to TOS, sucked in the eyes of the majority of tv viewers and ST fans..... and ended up getting canned well before its time?
As I see it, if they were going to tie Enterprise in with the rest of the shows and overall story line, it made the most logic using cast/crew from TNG, then any other of the shows, since A) Picard's Enterprise was responsible for creating the NX-01 crew in the first place and B) Trying to use any of TOS cast/crew today would look pretty odd if one was trying to flash back to an older time/episode in TOS (Sisko and DS9 crew already did that).
In regards to some complaining it was a TNG episode because "The only real characters were Riker & Troi and everybody else were holograms" or "That's not how the story really happened due to Riker's interactions in the holodeck."
^ The story revolved more around the Enterprise crew then it did with Riker's issues with the Pegasus mission. Riker's problems was just the base for why he was looking into Enterprise's last mission. While he was interacting with the holograms of the Ent crew, the information was based around the mission, what actually happened, crew personalities through logs/interviews, etc. etc..... far more information then what Geordi had going for him with his re-creation of Leah Brahms which was also done before the various advancements with Holodeck technology by TNG's 7th season.
Riker wasn't just getting the facts on what happened during the Ent's last mission, he was also getting decently accurate insights from each crew member's personalities based on the crew's recorded/documented experiences.
And here's some food for thought:
http://memory-alpha.org/wiki/Chef_%28Enterprise_NX-01%29
Chef was never properly identified with a name or face through the entire Enterprise series until the final episode, which we're giving Riker as being the chef.... what's the possibility that Everything seen on Enterprise, from Season 1, all the way to the finale, was based around holodeck simulations and the observer of each mission filled the role as Chef in the programming?
"Chef was never given a name beyond his title. Chef was a character who was never seen, nor heard, with exception of the purposely cropped shot of the character that appeared in "The Catwalk", where he was played by regular background actor and stand-in Richard Sarstedt. This information is from the call sheet, where he was credited as Richard "Isaac Hayes" Sarstedt, a reference to singer Isaac Hayes, who portrayed the character "Chef" on "South Park" for nine seasons.
In a potential story pitched by Mike Sussman, Chef, played by William Shatner, would've been brought by Daniels into the 23rd century, preserving the timeline by impersonating a legendary descendant during an important historical event."
Added:
Another thing I'd like to add is that I think the other reason why they used the Holodeck as the playing field for the final episode, was because the original intention on ending Enterprise was supposed to be near the end of their trek and show what their overall accomplishments were, ie: forming the Federation..... but to just have it as its own episode like the rest where it jumps from year 4 to suddenly year 10 without explanation, would have been even worse then what everybody's sitting around complaining about now.
You'd have either a story that took place in year 4 that explains a situation that everybody is magically accepting that the NX-01's mission was a success after only 4 years of space travel and then the federation is formed (a bit more unrealistic) ~ or have it jump to year 10 like they did (but without the holodeck situation) and be left there with yer thumb up yer arse wondering wtf happened to the last 6 years in between the last episode you watched?
