A pre-alpha build of Underworld showed enemy AI actually going for cover and using squad tactics instead of just suicidally staying in the open to get picked off (which doesn't sound like much, but it's revolutionary for the series). Lara has also been given new melee abilities, including the use of a pole to whack jaguars and send them scampering. Not riddling creatures with bullets should make the animal rights people happy.
Check it out and prepare yourself for the inevitable question, "Who is the cooler tomb raider? Ms. Lara Croft or Mr. Nathan Drake?"