Bowman is going to OU because: undefeated. They don't play the same position at all, so outside of just raw numbers I don't think they have anything to do with each other.
I think the bigger question is that with McKinstry's commit to Alabama does this move by Johnson clear a spot for JUCO CB Kyhree Jackson. The Tide now have McKinstry, Smith, Williams, Jackson, and Calloway. If you are 4th out of 4 at your own position in just your singular class at Alabama the chance of you getting to the field vs. guys from 4-5 classes is pretty fucking slim.
If I was a betting man I'd say Johnson leaving has to do with Jackson not Bowman.
I thought that Prophet Brown, AJ Green, and Caleb Johnson all filled a role that the Sooners do need and identified. An insanely fast CB prospect/project with the ability to turn and run with the smaller/faster WRs that are prevalent once again in CFB. Always surprised that they didn't just get Green and move on. Green seems like a kid that would be much more likely to stick around Norman for 3-4 years as they develop him. There's a lack of top end speed in that CB room right now and even though any of the above 3 guys would be a project in terms of technique they all possess the kind of speed that is lacking in guys like Harmon and McCutchin.