Is it unreasonable to think that Sale will be back and will be elite by August 2021? I don't think so.
Is it unreasonable to think that ERod will be back and healthy and post an era between 3.50 and 3.90? I don't think so.
Is it unreasonable to think that JDM, X, and Devers will be 30 hr, 90 rbi, .300 type hitters in 2021? I don't think so.
Is it unreasonable to think that Barnes and Workman can pitch much better than they have this year, and that Hernandez can be back and productive in the bullpen? I don't think so.
Is it unreasonable to think that Verdugo is good and that Benintendi will be much better? I don't think so.
None of those, taken individually or even collectively, are unreasonable thoughts. If they happen, this team will already be light years better than what it is now. It simply wouldn't take too much for this team to be a contender for the playoffs. Honestly. A (healthy) rotation of Sale, ERod, Eovaldi, and Perez is pretty solid. A bullpen anchored by an effective Barnes, Workman, and Hernandez can be pretty decent. And a lineup with a "normal" Devers, X, JDM, Verdugo, and Benintendi should score runs.
So the additions would be: another starting pitcher and a couple more quality bullpen arms. If these totally reasonable things above happen then they really shouldn't need to add much to be good again. But this year...omg they're missing Sale, ERod, and Hernandez, and they're getting NO production from Devers and Benintendi (who's now hurt), and JDM has way underperformed. This team looks awful because it's ALL gone to hell at once this year.