Based on the pictures published in the local paper I think the new marina and pier will be a great asset and improve the attractiveness of the seafront. At the moment, the marina is almost hidden away so bringing it into the outer harbour will, of itself, be part of the attraction. There'll be plenty of vantage points to watch the comings and goings of the port and marina, including the marina curve and a new pier.
Obviously the design will have taken account of tides and other matters beyond me, but in terms of quality, I think the plans look exciting. The Prince of Wales pier in its current form already has exposed sheet piling facing the beach. If anything, once you have boats in the marina, the seawall probably won't notice.