The Rangers last year for 7.9 fWAR from Eovaldi, Dunning, Gray, Heaney and Perez as starters. Some numbers got cut a bit short by mid-year additios of Montgomery and Scherzer.
The Sox got 7.0 fWAR from Crawford, Bello, Houck, Paxton and Pivetta. Again, most of these guys did not start all year. (Only Bello did.)
The Sox lost Sale (2.1 fWAR) but added Giolito (1.0).
Right now, Roster Resource has the Sox starting Giolito, Pivetta, Bello, Crawford and Houck. I think the goal should be to get Houck back into the bullpen permanently. I'm just not so sure the imposed budget agrees with me.
That still leaves what I thought was their biggest problem - defense. Rafaela and Story represent big upgrades, but doubtful they are enough...