If gamefreak is paying ANY attention at all, they'll add a bunch of new male clothing in Z, and the option to remove hats (Maybe even some more hair color options + more male styles?), because right now you simply can't make a male trainer that looks anything but generic.
Females have such a wide variety of options that you can really make something fun and interesting, even brightly colored. Males don't even have access to a pair of white pants. They really do need to get on that. I still don't think they'll put in crossdressing, and I frankly, don't want them to. As
>>16821991 pointed out, they don't use the same model, so it would require retooling the female clothing to fit a male model and in turn we wouldn't get any new male-oriented clothes due to the time and effort involved. Frankly I'm more interested in making my male character look male. Nothing against traps, but you have to realize that that's a very small subset of the fanbase that has the desire to crossdress.
Either way, I'd put money on Z adding more male clothing and customization options across the board, or gamefreak truly has lost touch with the fanbase. No crossdressing, but at least enough male clothing that people might actually play as their own gender without fear of being a cookie-cutter PC.