definitely BCV for Stormalong Bay + Beaches and Cream; the pools / slide / splashpad at RVA are great but just not the same; sure RVA is shiny and new but that alone won't impress your pair of five year olds
if you want a three bedroom RVA is your only option (none at BCV)
also, if you go post COVID-19 and things return to normal, there is an amazing playground island at Caribbean Beach Resort that you can get to from either BCV (Skyliner) or RVA (quick walk)
make sure to eat at Topolino's for the character breakfast either way, awesome time for everyone but especially the five year olds! books quick though so you've got to be on top of it