IIRC it uses a movement point to attack anyway.
I prefer it does not auto-move into the square. Sometimes, I want to kill the monster without leaving my square, especially in defensive attrition wars.
Keep in mind this change was to encourage the use of multiple stacks.
With the occupy suggestion, don't attack them. If you want to attack just make sure you move other nearby armies to fill the gaps in your defense or use a roaming offensive fly-swatter force. If you're attacking and winning you should be better off defensively. One less army to worry about. Reposition your stacks accordingly. With roads you could pull a force from another front, refill missing troops from the attacking squad, or pool a crappy stack together with some loose units just to slow your enemies down.
Even if there is 1 unit there blocking the enemy, they will waste a turn attacking it. So theoretically as long as you or an enemy can produce enough single units to block an attack. The attacking force will never be able to push forward through the onslaught of single unit stacks. Taking the defenders square helps to avoid this.
Also when you attack a city. You occupy it on the same turn. (In FE I believe. Yet to do this in LH however)