The main changes will be to increase the number of reputation organizations (why they decided to split one of them across factions is beyond me) by three, with presumably a larger number of achievements in the events tab (Bounty Hunter Contract week), flashpoints (the two Titans of Industry flashpoints), planetary (CZ-198 planet), and perhaps companions (Treek). None of these are confirmed beyond the 3 new rep factions, to my knowledge. I guess we'll see how much they care about achievements if they bothered to add new ones or not.
There are most definitely new achievements for Bounty Contract Week and Treek - i saw them (and gained some) on the PTS. I believe there are also achievements for the new flashpoints (i seem to remember earning them but not 100% sure) but i have no idea about combat achievements for the new daily area.
If i remember correctly, there are more achievements in terms of volume and worth for the Bounty Contract Event then the Gree so those with 100% for the events will go down to below 50% by tonight.