If you have a theme that is quite restricted, all that people could do is fix up the EVs and Natures. Maybe the item. For example: Any suggestions for my star shaped team? should not be posted, as there aren't really that many star shaped Pokemon aside from Staryu and Starmie.
On the contrary, if you have a team such as: Any suggestions for my Christmas team?, that would be quite accepted, as there are many Pokemon that resemble Christmas themes: Stantler, Starmie, Staryu, Abomasnow, Delibird, Cryogonal....
So only post theme teams that you can change members freely. I'd say if there are 20+ Pokemon related to the theme, you're pretty good.