I'm not a programmer so I could just be talkin out of my bum here but I would assume a toggle button would be too much of a load on the servers having to constantly queue(right word) up 2 sets of gear for everyone in an area. I think the only plausible way would be to create non vanity servers for people that are all pent up on not seeing stuff like that and I highly doubt that is something SE would do.

That being said I am personally looking forward to it. I can empathize somewhat as I occasionally get in a mood where I don't want to raid with goofy looking setups. When those moments happen just have to group up with people that share those concepts.