Pelosi is trying to make it harder, politically, for the senate to bury evidence and testimony that's unfavorable for Trump, and by extension, any GOP senator who, after seeing all of it in public, still votes to keep Trump in office.
Good move on her part, IMO.
Ebs, in a normal trial setting, the House will present the evidence supporting the Articles and call testimony to support them. Trump's defense cannot simply consist of ignoring the substance of the charges while attempting to put the entire process of impeachment on trial.
Again, each and every rule, even any rulings by the Chief Justice, can be overridden by a simple majority vote of the entire Senate. It will only take 4 Republican Senators to agree with the Democrats in determining how the trial will proceed. Mitch is not a god in charge of impeachment, he has to get 50 others to go along with him.
I still believe that even hard partisan GOP Senators will take the trial process seriously because of the gravity due the trial and encapsulated by the oath each of them take to render "impartial justice." There's no ambiguity here. Impartial justice is a concrete thing, not a squishy aberration. If such a thing can be applied, the facts and evidence underlying the Articles are pretty solid and damning if one views them impartially.
At some point, each and every Senator who may dismiss these Articles will be called to justify why they did so. An whining about revenge for what happened in the House or complete denial that the evidence and testimony doesn't prove the charges won't be tenable after the public witnesses a normal, evidence-based trial where wild rantings and accusations unrelated to the actual charges won't likely be allowed or voted on by 51 Senators not wishing to turn their respected chamber into a Trumpian Jerry Springer show.