Re: おさげの女たんX
Everyone has different angles and hooks toward such matters, thinking futa is a dude or a girl is entirely arbitrary since they have both sets of genitalia and they tend to both function, but for me I'd say a female body in everything but a biological equivalent of a strap-on isn't exactly a dude, same as how a man with a vagina isn't suddenly a woman. At the end of the day, arbitrary lines in the sand aside, all it comes down to is whether or not the parts you're attracted to outweigh the parts you're potentially repulsed by.
Gender-bender as a theme works because it's inherently a fiction that explores hypothetical fantasies, it's not unusual for people to wonder "what would it be like if I were a girl/boy?" and for a fiction to explore that experience can be compelling, same as how a fiction of "what would it be like if I were a soldier" or any other fantasy or interest you might have. The sex and such can either be a bonus or the core appeal, but fiction in general is a vehicle with which to explore settings and scenarios outside of your normal life.
I can't really relate to taking gender as a psychological thing very seriously, I don't exactly identify by thoughts by some arbitrary code or set of rules, and the idea that I think the way I do "because I'm a boy" is downright silly, and the same goes for fiction, don't really care what's going on in people's noggins, if there are tits it's good, and more tits is better, futa to me is really just a case of having normal heterosexual sex with an extra pair of tits in the mix. Similarly futa on futa is just shite because there's an extra dick there that does nothing but repulse me, much like how a futa with the full package is just pointless extra baggage that doesn't appeal, might as well give the character a beard at that point if you're adding repulsive decor.