-Atk/+Spd Ike: Salvageable?

You can run a Heavy Blade QR set if you run an Attack + 3 sacred seal on him. That would let Aether proc about once or sometimes twice in a match. Otherwise, you could build him as a Fury Vantage build. That's still very good, and comparable to Ryoma with that build, just a bit more Def and less Spd. Which you could run a Speed + 3 seal to counteract as well. So, all is not lost. He's still very usable.

I have the same Ike, and I just left him with his former set, and added Swordbreaker. With his 32 def and 34 speed, any red sword unit or green melee unit will have a problem trying to beat him, with that bulk. He takes down some mages fairly well, they won't be doubling him much.