Again, you can't rationalize what ENT would be like if it was the first spinoff, because a prequel to TOS made in 1987 would be nothing like what we got in ENT. It wouldn't even be called "Enterprise;" it would probably be called "Before Star Trek" or something like that. Now, putting aside for the moment that in real life, there'd be no chance in hell that a prequel to TOS would have been made in 1987, or that it wouldn't be influenced by Roddenberry (because in 1987 it would have), how would a show about the Romulan War/founding of the Federation look like? I'd bet that it would look very much like Top Gun, which was all the rage in 1986. A bunch of macho space pilots flying space fighters and shooting at Romulan baddies. And at the time, it might even have been a success.