I'm having trouble figuring out why he's a strong pick. I understand that he's a huge lane bully that beats almost every other top laner, and can 1v2 the top lane and Jungler in some cases, but what do you do outside of lane?
It seems like he's just a meat shield once his damage falls off, what is his role after the laning phase?
Renekton has always been an early game bruiser with some pretty harsh fall off.
He is listed a Fighter/Tank, which fairly well describes his role transition. Early on, his base damages and sustain lets him take the Fighter spot top, bullying out many lane picks. However late game is a tank; in the sense that, as Riot has defined one of a Tank's roles, they deal very little immediate damage but, if left unattended, can stack up quite a bit of damage. Same goes for say Amumu (although he's significantly tankier), the mummy doesn't deal a ton of damage all at once but if you ignore him the entire time he'll drown your team in his tears and grind you down.
Renekton brings low but steady AoE damage through his Q and E, and his W stun lets him peel or try to lock down an enemy. His Ult's AoE damage lets him grind the team down, all the while sustaining himself off his Q.
Still, his stats and older kit hold him back; like his brother he can be kited well when his E is on CD, and his entirely melee-range kit makes him even less reliable than your average pick.
early game lane bully, if you can snowball hard with kills and late game he's a bruiser, if you play him like a tank late game build 
and 
, both stack with his ult so you can sit in the middle of team fights and do huge damage. when i play him my end game looks like
or
: CDR boots can also be built if the enemy team isn't putting out much damage.
: Stacks with your ult, if you're losing lane early try to rush this.
: If i'm doing decent mid game investing into this could be good.... after tier 2 boots and brutaliser
and or,
: If your team needs more tank
:^^
: early damage and builds into 
, combos well with 
and
: can combo well with 
:if your greedy
