Personally I don't think the quay would benefit from a cheap chain pub backing onto it with a terrace area, especially not populated by the kind of crowds Weatherspoons draws in. Look at all the fights that happen in the Liverpool arms (not all involving Drew Pritchard), and then multiply that kind of trouble by tenfold, with the introduction of cheap booze. The quay is a lovely place, made far less lovely by all the drinkers clouding the air with smoke from the Liverpool Arms. I really don't see how turning the quay into chav alley is going to attract people into the area, and if people really want to visit a Weatherspoons, they really don't need to travels many miles to do so, either from their own doorstep, or from their visit to Conwy.
The building design is an improvement, but that's as far as it goes.