I visited Haverfordwest November 2017 and also stayed at the Mariner's Hotel. I also felt sad that haverfordwest has changed so much. On Market Street, the butcher, fish monger and green grocer are gone. Most the the shops are empty or replaced with some sort of fast-food point. Tourist Bed & Breakfast seem to be the primary income for the area.
Newgale looked just as lovely, as did Broad Haven and Little Haven. The weather was still the same - lot of rain and strong winds :)