Zoro was not that bad. He started around low mid to mid high tier (Y3C-Y2C) post-TS and within one arc went beyond high tiers with two power-ups not really that bad, though obviously one opponent in-between might have been better.
Sanji on the other hand went from being a mid tier to mid to high mid high tier, it´s definitely a crazy jump.
Kind of underlines that Oda did not know what to do with him post-TS, hence all the suit and exo stuff, also how random HM apparently was.