I've done something similar to this build ever since the Kass rework. It's way better than straight AP now because of all the mana and tankiness you get, but still weaker than pre 5.4, obviously.
tank kass has been a thing for awhile already.
I somewhat agree, played as a bruiser with a low cd gap closer can work pretty well with him
Tank Kass has been a thing since season 2.