Europa Barbarorum (EB) also has very descisive battles, as armies are hard to raise and maintain. (
http://www.twcenter.net/forums/forumdisplay.php?f=31).
If you are a fan of vanilla and do not want to have the slow down of your computer due to EB's background scrips, I would suggest this excellent provinicial campaign made by IceTorque. It features two turn recruitment which limits your and the AI's ability to create armies, so makes the battles fought more critical. (
http://www.twcenter.net/forums/showthread.php?t=55389).