Cloak is too conflicted often times imo. Frank would just wreak bloody havok everywhere. This is more of a case of who would be less "bad" as a ghostrider more than either one of them being good at it. I go with Cloak, there's less of a chance that everyone dies for littering on the sidewalk or jaywalking.
OK maybe I didn't think that one through all the way. I was thinking of Cloak because of the whole Void thing and ignored his persona. Frank I was just thinking that being the Ghost Rider would be like Frank's ultimate destiny kind of thing.
if frank became the ghost rider we would need a major crossover just to stop him in his crusade of vengeance/justice.. and i would read every page of that crossover! in a way its the problem of frank working to well as a spirit of vengeance leading to a downward spiral of crap. but out of the given choices id still pick him.
be interested in a longer list of people for the role of 'ghost rider'.
thats been proven often enough but bringing him up is rather unimaginative. cant think of anyone who hasn't held the mantle before who could do the part justice?
castle would be the best fir. the GR already has the power to traverse dimensions (although most hosts are incompetent with it) so cloak's power is redundant