I had low expectations of Waikiki beach, infact I wasn’t planning on visiting it during my time in Oahu but, you know what? I went and it was surprisingly lovely! I can’t comment on the whole beach, just the segment 100m either side of the Sheraton.
Beach is clean, water is warm and everyone has massive respect for any sea turtles who swim a little too close and gives them the space they need.
It’s a family beach, it’s pretty chill, there’s always an ABC within easy reach for drinks and snacks. Always plenty of people kicking about to make it safe to visit at dusk/evening.