Well, yes people do say that FP did have a lot to do with TOS and LiS did inspire VOY a lot.
Like I said, B5 had the same type of "building a joint-community" story with it's warring races and the like and as such it's the chief example ENT's own take on the Birth of the Federation would be. As such the core similarities would draw comparisons and inevitable negativity from the fanbase in the form of "they're just ripping off B5 with thei insterllar community stuff" no matter how well it could be done by the ENT team.
As for politics, ENT did try that even in it's first season and got nothing but negative reactions for it which would discourage any further attempts. Why bother doing it when our every attempt has been rejected by the fandom no matter what? At best they'd just get "this is nice and all but it's not what Trek is about because it's just about the humans".
Most fans just blathered on about "I don't care about Vulcans and Andorians being enemies, I don't care about how Humans and Vulcans weren't always okay with each other, I don't care that maybe there were other enemy races, I just want to see fights with the Romulans!".
Spock said they were primitive ships with primitive weapons, meaning even the effects would have to be even more dated from what we saw in TOS otherwise it's just inciting another "The tech and effects are too good looking! This is a slap in the face to everyone who worked on TOS!".
The war couldn't be done well, if canon was preserved, because this means that the opposing sides would never even meet or anything. They wouldn't even be able to use the Remans as soldiers the Allies could see because the fandom would be in an up-roar over the Remans being in the war even though it would make sense. Why? Because TOS never said the Remans were in the war.
The Coalition of Planets, Vulcan Reformation, Andor-Vulcan tensions, none of this stuff violated canon yet STILL got nothing but negativity from the fandom. It's all the proof needed to know that they'd never accept anything the staff could come up with no matter HOW well done or canon-friendly it was.
As mentioned by Myasishchev, the Xindi made the "fans" have a field day even though they don't violate canon either. If it had been the Klingons or the Romulans who did it, the fans would have howled their guts out over it too since no other show mentioned Florida getting zapped.
As for naming the ship Enterprise, they'd just incit further fan wrath by doing so because they'd go "TOS+ never mentioned a ship with that name, so it doesn't exist!" along with "TOS+ never said there were famous people back then, and if they HAD existed they would've been mentioned! The whole show is a slap in the face to everyone who made every episode of Trek before this series!".
Just because some fans might not like ideas doesn't mean these ideas aren't bad. Still, what does B5 have to do with Star Trek? And I don't think B5 would necessarily be the model for a community building interstellar storyline. There are a lot of sci-fi properties the writers could look at, but I'm assuming they would look at real events first. Such as the Coalition of Planets being something like the League of Nations, a failed forerunner to the United Nations, which could perhaps be a model for the early Federation.
True, I had my issues with naming the NX-01 Enterprise because it didn't seem to be a ship named that mentioned before, however someone-writers and/or fans got around that by pointing out that the NCC-1701 could be the first Federation starship with that name, which left it wide open for Earth ships to be named whatever. However, I think it was a lazy choice that invited comparisons between Kirk's ship and Archer's.
What's primitive to Spock in the 23rd century would still be advanced to us in the 21st century, so I don't see what the problem would be showing the Romulan War. If some fans thought it violated canon, so what? They would still watch the show more than likely.
Obviously you can get around the never seeing a Romulan thing somewhat by having the identity of the Romulans being a closely guarded secret, and/or by having every one that seen a Romulan draw their last breath. Also, showing that the Romulans don't take prisoners, except in a few instances, could do that. Or having them in full armor that perhaps disintegrates if compromised, sort of like the Chigs from SAAB. I mean, keeping them fully armored, like the Breen, could add some extra menace to them without violating canon. The Romulans could've also used automated ships, which was established in the Babel storyline on ENT.
Also using the Remans as shock troops, and even though Riker sort of messed that up in NEM by insinuating that the Feds don't know much about the Remans, the writers could just chalk it up that he forgot to mention the Romulan War, or that even though Earth fought the Remans, they learned little about them. The Remans fought to the death and were hard to capture so it stays somewhat true to what Riker said in NEM. There's always ways around stuff if you tweak it correctly.
And a few canon violations aren't such a big deal if the story is well done. TOS was written in the 60s and ENT in the 21st century so the writers had to accomodate for that. DS9 and ENT moved the date of the Eugenics Wars and I didn't see much of a firestorm about that because most fans understood that it wouldn't work leaving it in 1996. I think fans would understand the changes regarding visual communications in the Earth-Romulan War. But even with that, maybe the Romulans had the technology but didn't use it, maybe they only used vocal communication as another way to play mind games with the humans?
One other thing, I think you're assuming that every Trek fan is a TOS fan and that's not true. I like TOS but my favorite Trek shows are DS9 and TNG. And even though I am a TOS fan, I don't know every episode line by line, or care enough if minor things are tweaked to synch it in line with current technology or current events.