Actually, for all I like the personal aspects of Toko so much, I feel about the political ones the same way I feel about the political aspects of Zutara. It would be a raging mess. I get the feeling the Fire Nation at least carefully breeds firebenders for heirs, and therefore, no powerful benders from other nations may apply. No way Toph's kid's going to be anything but Earth, even with Zuko mixed in. It would be a nightmare.

And Toph would hate being royal so much.

And someone has to write this now. Really, yes, they have to.