His W ensures he isnt ignorable in a fight, I just wish it wasnt so much of a KS move with its mechanics and my general use of voli as a tank.
His E is awesome for early game minion waves as well as a slow, Couple that with flip and exhaust and you've got a very dead carry.
His R is free damage as well as an aoe effect. Again situational when he's a tank but it puts that bit extra pressure on team fights.
Generally ill build him atmogs with wits end. Then its situational. But overall i dont think he deserves a lot of the hate. Ive nailed quite a few people with frenzys bite simply because they did not know volibear well enough. Its fun :p