There is no need for an incentive. Take the mechanics as intended, instead of as you want them to be, and think it through.
Being able to build structures is an incentive. Anyone who wants to grow his corp first, before he shows some balls, can do so. Anyone who does not want to go to war will not go to war. There is absolutely no reason to bait people into this, and it would go counter to the whole point of the change!
Rewarding people for playing the game is ■■■■■■■■, because it makes people play the game for the reward instead of game’s sake. Let them choose their path without trying to manipulate them into something they might not want!