Wild idea for the new #Stargate series: Lord Yu and his First Prime barely survive ReliCarters attack. Yu's body is wrecked and on the way out but his symbiote is mostly fine, his First Prime is in rough shape and with a dead symbiote. He offers his body to Yu(that dude absolutely would). The offer is accepted.

Yu substantially recovers, much of his dementia being revealed as host aging more than symbiote aging, but isn't able to completely dominate all the time. He and his First Prime function much like a Tok'ra, though not actually part of that movement.

Not an ally to Earth, but his interests still being elsewhere in the galaxy he's not necessarily an enemy. A frenemy to Earth, basically.
Goa'uld rarely bond with a Jaffa, but it does happen in desperate situations.
@anniethebruce I always thought Yu (the Goa'uld) himself was too old in order to change hosts and also the reason for the dementia. Not the host.
@mugentoki That seemed to be implied, though I don't recall if it was 100% confirmed.

Point is though I'd love to see one of the old Goa'uld turn up, someone significant without it being something silly like "oops we missed a Ba'al clone" or be one that is too heavily opposed to the SGC. Yu would be perfect for that, and his survival, while not likely, isn't as difficult to justify as it is for, say, Apophis or Chronos or someone.

Might involve some minor retcons but Yu seems like the best of the old Goa'uld to fit into a new series. Also I thought he and his First Prime were cool.