The prospect of youkai!Gin is exciting and something I would really love to see Sorachi play with! On the other hand, I'm almost afraid that would change the tone/mood of Gintama's story. Then again, it is Gintama and it always does the unexpected, so if it had to be anybody writing that, Sorachi could pull it off best.

...I've considered writing up an ace!Gintoki manifesto, can you tell? ^^;

Same here. XD
(And for that I blame you.)