I sincerely wish more fujoshi had your sense. What you describe is exactly what it is like for gay men in real life. I know a few "exclusives" (only top or only bottom), but they are the exception, not the rule. Roles don't switch much in yaoi because it is written for women and try as they might, topping just ain't gonna happen... not without some hardware. LOL I don't like too much realism in my yaoi stories, but I do like realism in the characters. So, to me, reversible couples are the best! I'd love to see some switching in the same scene. THAT would be hot!
the same reason the uke is usually much smaller (over all and in penis size), can self lubricate, and is feminine in character. The seme is always large and muscular, with a large penis, and very masculine traits. Making the sex as straight as possible makes it more acceptable to straight readers as it is something familiar and comfortable
I completely agree with everything you've said and feel the same way. And here, a present just in case you haven't already found this gem: I love this couple, and they do switch in the same scene! http://www.mangago.me/read-manga/mukizu_ja_irarenee/
Did you read one of the latest updates to Bitch Club? The sex scene with Yuri and his stalker involves some hot switching back and forth. For a really hot switching one shot http://www.mangago.me/read-manga/satou_kun_ni_wa_kanawanai_sachimo/
I tried getting into Bitch Club, and it was great at first, but I took a break from manga for a bit. When I came back, I just couldn't get into it. I think it was all the extraneous plots and characters. I probably got lost. LOL The manga you posted a link for is an awesome one though. On top of being hotter than hell as a seke party, it is also scanlated by ExR. One of the best scanlation groups out there now, IMHO.
I don't know... Maybe because I'm a sucker of reversible couple that's why and I don't see anything wrong by being bottom once in a while even if you're a top specially if the one doing you is the one you love. Well, it's only my preference anyway.