Yeah, the increased fuel consumption would probably also be an issue, plus a higher personnel requirement with 4 crew instead of 3 for the 64/72/80s. With that in mind, the best new armor for Ukraine would probably be K2s from SK/Poland, down the line - at least they'd have similar crew and fuel requirements.

We still might, but it'd be a total change in equipment for them - all of their practice, training, tooling and ammunition is for variants of Soviet tanks. US tanks would represent a total change in that and NATO countries would have to supply all of the ammunition for them - I'd imagine that's why NATO countries like Poland have been dumping their T-72s into Ukraine, they were planning to get rid of them anyway and they're easier for UA to use.