But even with his changed testimony, if I heard the NBC Nightly News correctly, he still did not tie the quid pro quo back to Trump.
He tied it back to exactly what Biden did when he asked for a quid pro quo by withholding $1 billion in aid -- reducing corruption in Ukraine, and making a public statement to that effect.
This is, btw, exactly one of the three reasons that the White House has articulated for holding up aid in the first place: a) Trump not liking foreign aid in general; b) wanting European nations to do their part; and c) combating corruption in Ukraine.
There's nothing new here, and there never has been anything wrong in desiring and working towards any of these as foreign policy positions and doing so by withholding aid. Using quid pro quos have always been a part of diplomacy.
Even what Biden did in taking actions to pressure Ukraine that enriched his son could be fine, though it's so fishy that it certainly merits a real in-depth investigation. And certainly naming names of possible sources of corruption that need to be investigated as part of an anti-corruption drive is also fine, assuming that there is sufficient cause to do so. The action of Joe that enriched Hunter certainly smell fishy, and fishy stuff should be looked into. Again, just because Joe is running for president doesn't put him off limits; in fact, it is for just these types of reasons where the politically powerful are treated by a different set of rules that got Trump elected in the first place.
Of course, the aid was released on 9/11, and a statement that an investigation into Burisma was made on 10/4, so even there, stuff doesn't add up even if it were inappropriate to hold up aid to make sure folks in Ukraine don't steal it wasn't a good idea in the first place.
EDIT: As I've said from the beginning of this kerfuffle and see no reason to change now -- the real issue is whether or not there is proper predication for an investigation into the Bidens. All else is smoke and mirrors.