From a pure QB perspective . . . Luke just is never going to be the guy to lead NU back, IMHO (I'm not sure Frost is as a coach, either, but that's a whole other depressing topic). He's a remarkable athlete who could have a huge impact all over the field and as an occasional QB with some specific packages. But I'm afraid we saw that the passing game is his kryptonite. He just doesn't have the arm strength, accuracy deeper or the instincts for what this offense needs in the passing game--and I don't think that's something he can develop to a high enough degree and fast enough. Not his fault. He hasn't been a QB very long.
I'd LOVE to see him be at NU and get plenty of action as a "slash" type player. Play some WR and RB and be a bit of a Taysom Hill kind of QB where he gets some series where he can either run or suck the defense in and make them pay with an RPO. But not sure that's what he wants. If he wants to be a QB only then it might not add up.
Whatever he does, he's a great kid and I wish him well.