I'd be inclined to think that the one that gets dealt if it comes to it is Bob. There is no in house cover for Panarin, meanwhile, the jackets have an in house goalie that could fill the need, as well as having several potential options to replace Bob if they need to (elliott from PHI, Howard from Det, etc etc). Jackets being in a playof spot makes it a tough sell to get rid of Panarin unless theyre getting someone back who could 'fill' his spot (not his production).
To add, it seems like Bob's situation is that he doesnt wnt to be in columbus anymore. Panarin hasnt ruled out re-signing in CBJ (last i heard, anyway), just that hes interested in getting to UFA. I dont know that the chances are high, but they're definitely higher than bob i would think. Not trading him also allows them to offer him that 8th year.
Do agree that Panarin definitely returns more though.