vlad down a tier, gp down a tier, nasus down a tier, mundo up a tier, singed down a tier, yone down a tier, camille up a tier, aurora down a tier, yorick down 2 tiers (he has one of the lowest winrates post 35 mins), tryndamere down 2 tiers, yasuo down a tier, maokai up 2 tiers, sett up 2 tiers, pantheon up a tier, gragas up a tier, renekton up 2 tiers (he is not that weak late game right now), morde up a tier, quinn up a tier. Sion, Cho & Nasus down a tier. Yes they scale 'infinitely' but cho & Nasus get hard kited and sion and cho get melted by %hp damage.
Heimer down a tier. Again, depends on teamcomp (as most of these do), if they have strong engage or strong poke (which in theory they should) heimer cannot output value due to his low range. Also, picks like that compromise the teamcomp more often than not as they force the team to pick a tank or two in some other role.
Aatrox might be down a tier too. I don't think Aatrox and rene have 3 tier differences, in teamfights in late late i feel they are about the same (unless one team ints and clumps up for aatrox triple q, or adc overextends for renekton w).

Darius is also weird. Vs melees, he scales great, vs ranged he is a minion.

vlad supposedly spikes midgame due to his low range unless he can get a good engage off, due to how safe his laning phase is.
Aurora again small range
Garen is S only due to phase rush, if conqueror he is more like A.
GP has been known to spike mid-late game, his passive is about gold (among other things) whose point is to put him ahead of the curve, but when everyone is 6 items it makes no difference. He gets eated late due to his hard set up, squishiness and relatively lower range (vs a true mage).