Agrred the Klitschkos did struggle against other SHW's they can't use their biggest weapon which is there size against them.
The biggest advantage SHW fighter have is the slack approach to punishing clinching. If Wlad couldn't clinch he wouldn't have dominated for a decade. Or at least he'd have done so using infighting ability if he is capable. Clinching should only be used as a defensive resort when trying to survive. Simple solution, clinch more than twice and you lose the round.