As I've been gaming out the roster in my head, so much depends on what we're going to get going forward out of JDM and Benintendi, and I guess on what the FO anticipates we're going to get from them.
If those guys rebound to the neighborhood of their career trajectories, this could be a very good offense in a hurry. Let's assume Benintendi can get back to (or improve on) his .280/.350/.440 ways and JDM can get back to slugging .550. Career norms, in other words. A 1-5 lineup that went something like Verdugo, Benintendi, Bogaerts, Devers, JDM would score a ton of runs. Benintendi and Verdugo are both LHH with .350ish career OBPs, small/no platoon splits, good contact skills, and moderate pop. Put those guys in front of a Bogaerts-Devers-JDM 3-5, and it would put a ton of baserunners on for the high-SLG, high-K% guys we might see in the 6-8 spots like Dalbec, Arroyo, and Chavis.
The question of Rosario — nice player! — is a good example of this. You could imagine a Verdugo-Benintendi-Rosario outfield being good on both sides of the ball, maybe with a glove-first CF like Almora as the fourth OF. Rosario slots in behind Martinez, and we have a 3-6 all of whom have posted at least one 30+ HR season, and then Bobby Dalbec and Arroyo (or whomever we find to man second base). That would be a deep, powerful lineup:
RF Verdugo L
CF Benintendi L
SS Bogaerts R
3B Devers L
DH Martinez R
LF Rosario L
1B Dalbec R
2B Arroyo R
C Vazquez
C Plawecki R
UT Muñoz R
UT Lin L
Possibly another 1B/LF/DH type (or C/1B) for the bench, ideally someone who hits LH, who can spell JDM, Dalbec, and/or the catchers against tough RHP.
But if Benintendi is in fact in free fall, you could also imagine a ton of downside, both defensively and offensively. You can't really trade him, at least not for any kind of return, until he shows something positive. Likewise, if Martinez still looks like 2020 Martinez, then he's a positionless slugger with a sub-.700 OPS and an untradeable contract — yikes. And if either guy is here, but playing terribly, our roster suddenly makes a lot less sense.