I'd say Pianeta. Mormeck was a decent champion at cruiserweight so at least he had that going for him. Leapai earned his shot legitimately by beating the extremely overhyped, but highly rated Denis Boystov. Pianeta was just terrible.
Leapai, without a doubt. Pianeta was borderline solid European fighter, Mormeck was a former CW champion (and he beat Ibragimov at HW), but Leapai... Beating overhyped Boytsov made him mandatory, which is the cruelest joke in recent boxing history. This guy was just an awful boxer.
Not this. Boystov was a fake set up mandatory defense for Wlad. He had zero wins from the WBO top 10 .. Yet he was placed #1 , even after pulling out of fights with WBO rankers Chisora and Fury. He ended up losing to the patsy that was brought in to legitimize his title challenge. Then Wlad went and fought that stool pigeon. Leapi had no more business in the ring than Mormek , Wach and all the rest.
Leapai was a more "justified" defense, in that he was just obeying alphabet mandatory. But Pianeta has a better resume than Leapai and would probably beat him. Duhaupas and old McCall were more formidable than Boytsov.
And how does a 50 somthing world rater earn himself a finial eliminator ? Nah , not justified. Not justified at all.
Mormek was without doubt the worst. A joke of a fight. Was 40 years of age, shot and hadn't fought in about 2 years. Whats worse though is the performance out of Wlad . A sick joke. He held worse than Ali held Frazier.
Granite chin opponents are always difficult, especially at HW. He had a better chance to upset Wlad with some lucky big shot.
Leapai and Pianeta are a tie for 1st place. Easily two of the worst title challengers in the history of the division.