I promise I read the entire thing, and will do my best to conduct myself in a rational manner.
You said string gauge should be chosen based on comfort for the playing style. I agree wholeheartedly. I believe that some people have an easier time playing on 9s. Why do most of them have such a hard time believing I have an easier time playing 11s?
You also said the tonal difference between 8/9 and 10/11 would be difficult to notice in a live setting to anyone but the player. Aren't 99% of the tonal considerations we make for ourselves? Don't we all play better (something non-guitarists WILL notice) when we love how it sounds and feels?
If that stuff happens with 7s, be like Billy Gibbons and use them. If it happens with 13s, be like Nir Felder or Josh Smith and use those.
Speaking of Josh Smith, he has a really funny story about why he uses such heavy strings (13,17,28p,36,46,58, standard tuned). When he was younger and used 11s, he tried sitting in using someone else's guitar. He said he could barely play it, and afterward the guy apologized, said it was strung with 13s. Josh goes, "Well, that sh*t's never happening again," and switched to 13s after that.