I agree Coronado is great if you want a ton of soft sand. And yeah, Ocean Beach, Pacific Beach, Mission Beach, some of Carlsbad, and some of the Oceanside Beaches suck (I don't go to any of those).
For family friendly beaches, I would really try out Powerhouse Park in Del Mar (either sticking there or going 3 minutes south beneath the bluffs) and Fletcher's Cove in Solana Beach. And if you're up for a trip to Orange County, I think Salt Creek in Dana Point one of the best family beaches around (there are also good resorts around there).
And Crescent Bay Beach is one of the great hidden gems. It's surrounded by bluffs and tourists really don't know about it.
And then Crystal Cove in Newport is about as perfect as it gets and the Newport Villas are a nice place to say.
I actually like Coronado, but there is so much natural beauty around I think exploring is well worth it.