That's a pretty big assumption. I wouldn't think that the tax rate decrease required by taking an additional region would come close to offsetting the amount of gold you gain from taking it.
In fact, I'm nearly positive (haven't run the numbers, but don't feel like it's necessary) that under either the old or the new system, it wouldn't come close at all.
Not really a big assumption. If the region forces a 1% drop in tax rate all around, that can easily add up to eating away any gain the region provides. Especially true if you have big cities(1% drop is easily 100 gold lost in such cases, add the other regions and you quickly eat away any gain from a normal rural region).
