Ive usually found the beach to be very changable.
A decent storm can significantly move the sandbanks and gulleys, but these tend to occur more in the winter months than over the so called summer ( obviously! ).
The old river bed uncovers occasionally, but has been visible from Splash Point for most of this summer and looked very fishy, although i havent tried it.
Personally, i dont think the beach has been the same since the event years ago, when they had earth movers making a race track for motorbikes and quads that significantly changed the features between Rhyl and Prestatyn.