Actually, Valamir, it isn't specific to that setup, just benefits that setup the most. Like I said, I found that with those settings, the deck was stacked so far in my favor that it was too easy, so now that I'm used to keeping up with the AI expansion efforts, I've got the habitability turned back to the default setting. In fact, I may have maxed it out on my current game to see how different it could be.
I'm disagreeing because I don't see any of the problems that you discuss in your first paragraph (in post #9). I don't have morale problems on my planets, and I don't build morale boosters on my low-end planets. They don't quite pay for themselves, but my big planets don't either, so that's not really an issue. This may have to do with the fact that I puruse morale solutions by tech/trade goods rather than building social projects.
This also isn't a culture-push strategy. In both my previous and current game, I've got a lead in culture, but it's my economy that is towering over the other civs. In fact, in my previous game, I think I only converted 3 planets in a Huge galaxy. It was still a cultural win, oddly enough. The game before that was an Alliance victory where I wasn't even close to a cultural victory.
One thing I'm pretty sure that we'll both agree on is that if you have a planet with a class of less than 15, your very first priority, even before manufacturing center, is to get it up to 15. Oh, and don't waste money by building social projects with maintenance fees on low-end planets. They cost the same and give less benefit (absolute, not relative) than the same thing on a larger planet, hence less cost-effective. In fact, there's only three social projects with maintenance fees that I'll usually build on a planet with a class less than 20: Manufacturing Center, Stock Exchange, and Anti-Matter power plant. Each of them costs 1BC/turn and benefits at least one stat by 25%. I'm much more likely to boost production with a starbase, since it has no maintenance costs associated with it, and can benefit more than one planet. I will admit that it's probably more expensive in terms of manufacturing, though.
In support of your other points in that post:
1) Yes, especially when you're playing with less common habitability settings, you will need them to get to something.
2) I figured out fast that a starbase supports a planet, but a planet supports a starbase, for one other reason you didn't mention. A nearby planet gives you a place to park starships that can pop out and help defend the starbase, then retreat to the planet to repair faster. I don't like stacking the defending ships with the starbase because the ships normally get attacked before the starbase, and in most cases, the starbase is better capable of taking care of itself than the ships are.
3) Quite true, especially if the reason the planet is PQ 15 is because of a +15% civ talent. AI takes the planet, the planet immediately drops to 13 and posts an angry face. I've never had an AI not loose steam very fast when on the offensive against a bunch of planets like that
4) Cultural infiltration: While I agree with this, it's probably the weakest point, because the small planets don't have the influence the larger planets do, and if you're not careful and aren't backing up the planets with culture SBs, you can loose the planets due to culture.