As long as the opposing jungler is not lee sin or vi (hec is fine) sej, skarner and naut are fine in the jungle currently.
Amumu definitely feels really weak right now as he's far more vulnerable than other tanks (incl zac) as they have ways to escape the likes of lee/Vi without needing a monster to jump to.
As for Vi and lee, they simply do everything better than everyone atm, think about cinderhulk sej when it was OP. They clear faster, gank better, move quicker, duel better and secure objectives faster than any tank (granted they should, but other divers are significantly weaker than these 2 champs).
As for every other tank in the game, many are rarely seen in low elo on OCE, there isn't even a "most common" tank as it's all Vi/Lee. Shen and maokai could use some assistance in the jungle.
IMO cinderhulk doesn't need buffs as much as other champs/items/masteries (CoTC) need tuning as tanks were decent at the end of season 6.
One change that would really help tanks, would be nerfing the overall movespeed of mobility boots and buffing the debuffed speed (so you don't slow down as much). This would boost clears while providing the solid ganks of pre change mobies.