Renekton is perfectly balanced and very durable champion. You probably think he needs a buff because you build attack damage and expect to survive in the middle of the fight. He needs to be built tankier with arpen runes because that way he can be in the MIDDLE of the fight (which is where is he supposed to be) and dish out TONS of damage
It's unfair that Tryn get a better passive that TRen, and Ren has had the Fury system longer than him
Shyvana is more tanky in and outside of her ultimate than Renekton is, and does more damage than Renekton. Coincidence?