I'm going to go B+. I quite like what they did with the pen even if they didn't get a true lockdown guy. I liked the Cabrera trade and the upside it gives the rotation even if he does come with durability questions. I very much like Bregman at 3B especially because it pushes Shaw into the Zobrist role which is a big upgrade for the bench. So for the things that kept me from ranking it higher.
1) Yes getting Steele back should be a be fairly big for the rotation, but there is a good amount of uncertainty around Cabrera and the Cubs really needed a guy to slot into the top 3 of the rotation. That might be Cabrera, but who knows given his history.
2) The Cub offense is very deep now, but after losing Tucker I'm not sure they have a true elite bat. They've got a ton of guys you can pencil in for 115-130 wRC+ but no one is going to threaten that 150+ wRC+ territory. I also feel like they're bench bat short but maybe Alcantara turns the corner.
3) They rebuilt the bullpen on the cheap and honestly it looks pretty good, but man would I like one more good pen arm, it doesn't even have to be a closer, but one more pen arm in the tier of Palencia/Maton/Harvey.