Alpha testing videos have begun to surface. Here is what I have learned from what I've seen:
-Third person camera view is not limited to ranged attacks. It can be used for melee as well.
-Combo's appear to be much more fluid and fast paced than in previous games. They also appear to utilize more than one weapon type. In the past an individual combo has been restricted to either a gun, sword, or wand. (EDIT: I might be incorrect here. I may have seen a gun-sword in action. I know this weapon type exists in Phantasy Star Zero. However, the slashing and shooting effects of this weapon type could not be combined into one combo. It would be a nice change in PSO2 for a weapon which I thought was a neat idea but was executed poorly).
-Photon arts, Bullets, and Techniques appear to now work in a skill tree format. The skills in these trees also have passive abilities. For example, a skill that increases fire damage.
You may notice other small things if you look around for the videos on youtube. So far it looks like a familiar experience.