The concept of an ongoing impeachment process against every sitting president isn't that bad of an idea. In some governments, it's the fourth branch of government called the "Control". Perhaps Obama, Bush, and Clinton—all the way to FDR and Wilson—would have served the people better if they had an ongoing impeachment proceeding. It's tempting, but, for now anyway, it looks like a big waste of time.
The president's defense seems incredibly boring, but that won't matter. The Democratic prosecution omits key evidence, but that won't matter either. Every vote in the Senate has already been decided. These proceedings contain the platform for the other side to be added where there was only one side of what should be fair. Life isn't fair, but drama stops at the Senate floor. As with Clinton, there is neither basis to remove Trump from Office. Impeachment is a big deal, but usually falls to the popular opinion; voting citizens are the jury. Both times, all the energy from the House was spent on the Senate, which just let the House wear itself tired.
While one proceeding moves forward for show toward a pre-agreed verdict, another investigation continues against the faction that wanted this impeachment in the first place. A network of unhappy people from the opposite side of the political spectrum, largely in cahoots with the FBI and beyond, tried to prevent a president from being elected, then tried to remove him from office for something that didn't happen. In their view, justice is an illusion; they only do what suits them with whatever power they have. For them, might is morally right. Fortunately, democracies have systems in place to prevent power-defined morality touted by Leftist activists in America's legal justice system—whether judges or FBI.
The strongest evidence in this impeachment trial is the phone call read-out between Trump and Zelensky. It only seems inditing when heard in small snippets by people who hate Trump anyway. To everyone else, it is acquitting. Calling witnesses would stretch on and on and, for Republicans, would only serve the purpose of exposing the swamp that the FBI was a small part of. Democrats gamble that the Senate won't call witnesses, so House managers taunt the Senate about not calling witnesses. But, just how the president released the contents of the phone conversation by surprise, the Senate could decide to start the boring process of asking pre-written questions through the Chief Justice. The main purpose for Republicans would be to put accomplices on the stand. If that happens, expect at the top of the list the center of the phone call's discussion: Joe Biden.