I am now the proud owner of a +Res, -Spd Owain. Please help. I'm very sad.

Yeah that's what I got and I put QR in him too. Works fine.

Owain's speed is not as important as many people think it is if you're going with his base kit. He should always be next to someone because of Blue Flame and, if you kept it as his A slot, Atk/Def Bond. His Blue Flame will activate after being attacked once, meaning that, in most cases, he will be one shotting a lot of the units that he battles, and because he has the res boon, he can be a bit tankier against dragons.

If his speed is do problematic, then you can just give him Darting Stance for his Seal, or you can do Brazen Atk Res for even more OHKO potential. Close Def can work to ensure he doesn't take too much damage.