not a lot of assuming, we know when development started because sven told us when WOTC approached them after they were turned down the first time.
And id say after that ammount of time that theyve had, they probably got things like the combat system down at least in planning.
Mostly because , in an RPG, the combat system dictates a lot of the games content. If you got a real time combat system, chacnes are youll wanna throw in a lot more fights than in a game like OS because they wont last as long.
Combat, character creation and progression are the hallmarks of an RPG, logic dictates that you probably should nail those down before you start creating the worldspace.
and they did have plenty of time.
its assumptions but its assumptions based on evidence
