The best thing is to hire a car and visit not only Paphos but the sights near Limmasol and the Trodos mountains
The city is nice and gives you the opportunity to enjoy the raw beauty of rocky beaches. The harbor is pretty much always lively, but when it comes to nightlife you must know where to go.
Otherwise, you can stay even disappointed about it as in the majority of places not much is happening especially during the week. Keep in mind that the city center and the shopping are are quite far from the harbor (about 3 km), so if you like to walk in hot weather you'll be naturally fine. Other case scenario - you spend more money on bus tickets.