Don't really care if he gets "denied" or not; what I want to know is who would both be a credible nominee and be willing to accept the job? Are they really going to bring back Romney? I guess Paul Ryan could, but why would he risk all that political capital when he's already Speaker and could run on his own merits at some point?
Any candidates who have a credible shot in the general election probably wouldn't get installed in a brokered convention because they won't be acceptable to the hardcore right-wing base. The two I could see actually wining would be Collin Powell (if he's finally willing to step up in post-Obama era so he can reassure his wife that a black POTUS isn't a guaranteed assassination), or Susana Martinez (governor of New Mexico). Beyond that, who has a legitimate shot?
It's like anything else- too much inbreeding weakens the whole line. Repubs' economic ideology collapsed on itself in the wake of the Ownership Society & they've badly over-sold the base on a variety of other issues where they really can't deliver. They've just become more strident over the last 35 years. Otherwise, the last time they had an original idea they disavowed it when the ACA passed.
They also failed miserably on foreign policy, particularly in Iraq, but they obviously won't owe up to that, either. Their hard line rhetoric wrt Iran persists to this day even though it never has been constructive.
The reason they don't have great candidates is that they're not fit to lead, not with their heads buried in denial over their own failures.