i'm 2 days in and haven't made it to diamond city yet but are there any other established towns, fallout 3 had megaton, rivet city, tenpenny tower, underworld etc with merchannts, doctors, hotels etc, cause i'm not really interested in settlement building and hope they didn't replace already established towns with settlement building.

No. There's places like Goodneighbor, Bunker Hill, that one medical Vault, etc.

cool thanks