Achan hiArusa
Explorer
Playtesting through DDXP is all and good, but most people aren't going to be using D&D playing Wizard's adventures in a public venue. People must be allowed to home test the rules, where they take the rules home to their friends (and, of course, have them sign an NDA), write their own adventures, let the players break the rules, and run a homebrewed campaign. And they need a wide variety of people to test it, heavy Roleplayers, combat junkies, world-builders, casual players, and groups with everything in between. DDXP is not enough.