AD heavy fighter Renekton middle
I have tried some different Renekton builds in middle, including tank, tanky bruiser, and pure AD assassin, and I think that an AD heavy fighter (think Fiora or AD leaning Darius) Renekton in mid lane is quite strong. With a simple Maw rush, he can sustain and outduel any AP mid. He has 2 dashes, great base damages, good AD Scalings, 4 damage abilities, an ultimate that buffs his tankiness to give him survivability even without any/many defense items, etc. He is an overall good pick for mid lane, it seems. I, personally, think that I want to practice him and main him. With him being a manaless AD champion that has gotten buffed a few patches back, I think he is a perfect fit for the mid role; especially because of all of the other champions getting nerfed (along with DFG being removed, so he doesn't have to worry about cheese).
So yeah, try him out. I highly recommend him. If you get rolling, you get snowballing, due to his innate tankiness mixed with his massive damage. Just remember to level up your Q, then E, then W to max in that order; not Q, W, then E. The second E proc is much stronger, damage wise, than his W, and in mid you want that burst (plus the cooldown on his mobility spell).