Actually Victini doesn't use Wild Charge (it has Bolt Strike). But the difference is that Victini will often have to switch out due to V-create's side effect, making it easy to rack up residual damage. Both are also easily hard countered by Slowbro, one of the best Pokemon in the meta atm. (aside from the special Victini sets with GK but it's a general consensus that the physical set is far more threatening)
Crawdaunt is different because it can actually laugh at his counter (Chesnaught) due to Aerial Ace.
also OU/NU/whatever bullshit tier that isn't UU has literally zero impact on UU's tiering system, nobody gives a shit if Crawdaunt is like unviable in OU, what has been proven is that Crawdaunt is broken in UU and hence he gets sent to BL. Venomoth falls under the same logic (and honestly quiverpass is fucking cheap considering the amount of shit we have that can wreck the tier easily with a quiverpass such as mega tortoise/sheep/dog, nidoking, hydreigon, kyurem etc), though that shit was already broken in RU/NU anyway and if UU haven't banned it first chances are RU/NU would've done so by now. it's like saying that Deoxys-N/Arceus-Psychic should be unbanned because it's unviable in ubers...
The thing about Volcarona is that after a QD it's near impossible to revenge without LORD FLETCHINDER/scarf mienshao, the best special walls in the tier atm either crumble against it (Umbreon, Mew) or do jack shit (Florges), very few things can actually switch into it easily because of his coverage options (giga drain beats waters, hurricane hits flash fire users) and Fiery Dance is basically special Moxie (aka broke). All it really needs is like Defog/Rapid Spin support which is actually ok because we have decent spinners/defoggers in the tier (starmie, flygon, mew etc)