I couldn't believe when I saw Seth on FastForward (ABC Thurs 8 with a repeat Fri 8) as an FBI agent. His acting skills were quite good.
In a blog someone questioned "Do we feel like if he comes back regularly it'll help the show or just be weird?" I think he should come back as a FF semi-regular.
Then again he has three shows to oversee until Cleveland bites it and is replaced with the returning Futurama.
Just IMHO, YMMV