It'd be good if the Alpha people get early access to the editor too, and can use that to make a tutorial and sneak peak for us non-Alphas. It'd also whip up some extra excitement and interest in the game, I'd think.
Agreed. The first six months for a modding community are crucial. If the game can have a vibrant modding community up-and-running quickly, with plenty of lessons learned and documentation available from Larian devs and other modders, the likelihood of the game attaining NWN-style longevity goes up quite a bit. If the game doesn't have that kind of support and if user-made mods in the first six months amount to "Large Bressts Here!" and "Blue Sord Pak #345" then people will move on...