If the decision is based on the pool - that is an easy one, the pool at the Sheraton is very kid friendly and fun. The Westin pool is indeed very small and I rarely see kids there and isn't kid friendly. Your only challenge with the Sheraton pool is it tends to be very busy (get chairs early but even worse at the Westin).

Regarding the beach - it isn't tiny at all - you simply exit the pool area and there is plenty of beach in front of the Royal Hawaiian which is right next door to the Sheraton. The beach area does not disappear at high tide.

All of the oceanfront suites have been renovated (1 per floor) and are quite nice. I've been led to believe all the others are on hold but could be wrong.