-ATK/+RES Owain

Well he can still run an enemy phase build. I don't know how badly you need his fodder (wrath, blue flame, atk/ def bond). Attack+3 seal, team support can make up for that until you get a better copy if you do decide to keep him.

We have an Atk/Def Bond seal and we're about to get a Fierce Stance seal. You're fine.

You could give him a close def seal to make him bait in dragons as well as normal physical units.

BLUE FLAME INHERITANCE
To be honest Owain isn't the best stat wise, and there are some characters that can make use of his special better with better stats and BST. If you like him as a character then keep him. If you don't and don't expect to be investing heavily onto him, don't bother.