Really? I don't know anyone who thinks she was a good presidential candidate at this point in time, although in the future she may be. She might be vice presidential material as well, although I like her in the Senate.
His best argument is weak. He says yes all the allegations against Trump are true and he's done some terrible things that are indeed impeachable offenses, we just shouldn't impeach him. He thinks that the proceedings are too narrow and fast. Fast and broad is OK, slow and narrow is OK, but fast and narrow no way. It's just some sort of personal preference that he is trying to write into the Constitution on the fly. Another preference is that he would like for there to be an actual statutory crime committed, even though it's not Constitutionally necessary. He would just like it, that's all. Because that's the way it's been in the other impeachments. Let's see we've had three impeachments and this one is different. We've also had 44 previous presidents and to say that the current one is different would be one of the biggest understatements in recorded history.