The Dippers front 5 are very good, apart from Gakpo who is nothing special imo. Defensively they are flaky as you mentioned, they need another cb and rb to challenge City.
I agree but the quality of Liverpool's defence in the past was based more on the quality of their pressing than on the quality of their defenders. If they have the legs to press like mad and are a bit lucky, they can solve many of their defensive problems over the course of the season. Plus, they can concentrate on the PL. We'll be chasing everything and Arsenal will try to go far in the CL.
Are Liverpool back? Too early to tell, but they are likely to go above 82 pts, maybe 86.