The evidence that was improperly elicited intimately concerned his presidency. How he did business as a president via Hope Hicks and many privileged conversations with other people in the white house. They used those testimonies to try and show that Trump was aware that something wrong was being done and caused it to be done. Very unconvincingly I might add.
The entries were after he was already President so how is it believable that they were falsified to protect his run for President?
Trump did not even make the entries; his bookkeeper was the one who noted them as legal expenses. The bookkeeper testified that he classified them that way because they were paid to the lawyer. Trump had nothing to do with how they were classified as the bookkeeper attested.
The testimony from people who worked for Trump on official matters is prohibited. The prosecutors said at closing the Hope Hicks testimony was damning. If that is so the verdict cannot stand since her testimony is protected by executive privilege. Since Trump is not sentenced the verdict can be set aside.
I think it would be much worse if it was dismissed due to executive privilege. That would imply it was legitimate in the first place.