Rotation would be upgraded, The offense perhaps slightly down graded. the bullpen I'm quite happy with so I'd call it neutral, but the bench would be significantly upgraded.
So, I'd rather Bregman/Bichette because of the huge upgrade it gives the bench with Shaw, but suddenly Bellinger makes a good bit of sense. Plays RF, can fill in for PCA here and there.
As things are set right now, Mo is set to get a lot of ABs. Alcantara might get a couple hundred too. If the Cubs were to acquire Bichette/Bregman and turn Shaw into a Zobrist style super utility player, then who knows.
I can't see them trading Taillon given that Steele is going to be out for a bit. If Anything, going the 6 pitcher rotation is great to limit innings on Boyd, Horton and Cabrera.
I think the Cubs would be a bit hesitant to trade Alcantara as he's basically your back up CFer right now with no one else currently on the roster who can reliably fill in.
I mean there's some drastically different levels of value among them. Like Shaw+Caissie would feel real bad, but Caissie+Assad would feel pretty great.
I'm letting this lack of action annoy me far more than it probably should, but jesus Jed get off your ass and go get your guy. Stop waiting for people to fall into your lap.