There is zero evidence of Biden doing anything illegal in the Ukraine....none, zero, zilch.....
There is no problem with their being stipulations on it, the problem is Trump only mentions Biden, Crowdstrike etc....he does not generalize it, he is using the resources of the USA to politically benefit himself and that is illegal and impeachable and frankly downright disgusting actions. Trump by his actions shows that he is willing to work with foreign governments to advance himself politically in the the USA, I mean this just validates the entire Mueller investigation even more.....
As the details come out and Rudy's and others role in this becomes better understood I think that the depth and scale of this effort will be huge, there is a entire angle here not even being really explored with Rudy, Parnas, Fruman and Firtash and their ties to Shokin......of how these people used their influence and power to convince Rudy and Trump to go after Amb Yovanovitch to help facilitate Firtash returning to the Ukraine etc....again there is tons here really this is all just the tip of the iceberg.