1) People hated Braga long before he wrote TATV.
2) That's a pretty silly reason to hate him given it is pretty common for a former head writer to return to write the series finale. For example, Larry David wrote Seinfeld's final episode despite the fact he left that show's writing staff years earlier..
I think such a gripe is superfluous, to a degree. Obviously, a series finale is going to be remembered and referenced more than the vast majority of episodes during the show's run. It can , and I suppose many would say, should serve as the capstone of the production, certainly bringing loose ends together (well for the most part historically) and optimally providing a validating and satisfying definition of what the show embodied over time. I can appreciate these threads, but is it really justifiable to severely downgrade the show's worth if the finale diverges from hoped for expectations, is perhaps poorly executed, illogical, or even a total piece of crap? I wouldn't go so far as saying it's just one episode, but is it really so hard to decouple such a disappointment, relative or absolute, from the content of the program's true body and structure of work?
Even if a certain resolution is not presented, or obliquely so, causing significant degrees of general consternation (Sopranos), should an extended run of dedicated work, be so strongly tagged by that choice of a denouement? I really don't think that it should. I would much rather think of the quality, one would hope consistent, that was experienced and processed, and for me at least, represents the legacy and memory of the presentation. Longevity and reputation likely play roles in this perception, as well. I suppose that for a show that had a number of years of very good to excellent production values, acting, plotting, etc.it would be markedly more disheartening for it to wrap on a mediocre or worse finale, especially if it didn't particularly make an attempt to reconcile or even unquestionably recognize and honor essential aspects of the show's history. For a program with a shorter lifespan and more chequered history, that might not be as meaningful. In the case of Enterprise, we are talking about a limited period during which more distinctive and noteworthy elements of production came to the fore, and especially because that positive arc came at the end, not the beginning, I understand bitterness at the determination of how the closer was chosen to be constituted. But for me, it doesn't particularly detract from my view of a program that offered increasingly interesting and well executed stories over the last half of its run, and only was prematurely concluded because of reasons containing not even the slightest reflection or echo of how that capper came to be conceived.