I think all tanks should be ranked as is - i.e. if you fire 100% gold that's fine, rank it with no asterisk. Even with that, i'd rank like this (order of priority on each tier being indicative that it is better):
S - Pta, Standard B, Kmp 50t* (not played), 430, Type 61
A - E 50, T-55A, Char, Skoda T50, Udes 16* (not played)
B - M46, T-54
C - Cent 7/1, Amx 30
D - BC AP* (not played), 430v2
The list is based on damage farming capability, which is similar to carrying but slightly different (damage farming does not always = carrying, but there is a strong correlation). Reasons for rankings:
Tier 9 meds are a sweet spot as the best have tier 10 guns with very little drawbacks. It's why the Type 61 is S tier - it has insane DPM and muder-HEAT ammo. It has 5k DPM potential for the best players. Any gun that doesn't have 330ish prem pen can't be in S tier, hence the E-50 falling down.
Platform is still important, and tier 9 also works really well for flat track bullies. I included the 430 in S tier for this reason - in a tier 10 game, I would pick other tanks in lesser tiers over it, but all in all I think it belongs there.
I don't rate the T-55A that much. I want to like it, but the shitty hull armour and no gun dep and shitty standard pen makes it feel like either a shit 430 or a shit Kmp 50t. Either way, it isn't up there in S tier.
There are a few tanks i've not played and the opinion is based on playing against them/watching other people play them. Also, some I played years ago (Amx 30, Cent, 430v2), so maybe I'm wrong.