Individual hero skill cap based on abilities is an illusion; the skill it takes to play a hero is directly proportional to how strong they are in a particular scenario.
Take Cass and Sion for example: Cass is a 'high skill cap' hero (because throwing aoes and smartcasting E is apparently difficult), whereas Sions 'stun you, ulti, then right click with all my farm to win' is a faceroll hero. However, when you put them in the lane together, Cass will easily **** on Sion, harrassing him with little to no repercussions. To even be able to farm safely, the Sion will have to dodge every Q and not get zoned by W, essentially he has to know Cass better than the Cass knows Cass. For that instance, the skill cap of Sion is much higher than the Cassiopeia's.
Durrius is a low skill cap hero because of how strong he is in a dueling situation. You simply cant 1v1 because he was designed with stupid numbers that allow him to 1v1 people, one after another, with no downtime inbetween. If he actually had a chance of losing, if hitting the Q for the 50% extra every single time was necessary to win against another tanky derps, if he needed to time his W perfectly to reset his auto attack and gain sufficient CD on it from bleed stacks, if E didn't give free %arpen, if his ulti removed the bleed stacks so he'd have to think in advance whether or not he'd get the kill, he'd have a higher skill cap automatically.
TLDR- no such thing as a high skill cap hero that is a strong/OP pick.