I'm a division 1 player and even when the division 2 will be released, I wont stop playing 1. Mainly pvp player. Some things that should be different, at least I think so, are:
1) The new medkit system. In the dark zone if another player goes rogue on you, you don't have the time to heal yourself, even more if it's a group of 2 or more.
2) Down left it says that a player is rogue but you can't spot them without having to ADS them. In the division 1 it was perfect how it is.
3) The character movement. Seriously. When my character was running she looked like she had to go to the toilet ASAP cause she was running out of time. The same when she was walking backwards.
4) The lack of skill that can heal you as soon as you pop it, like first aid. We haven't tried all the skills, but from what was unlocked that was very important, to me at least.
5) I can't recognize what type of enemy I see yet, but it was an enemy in dark zone that kept shocking me and that shocked lasted forever. And I died. As soon as he would stop shocking I was trying to get in cover and heal myself with a medkit but I didn't have the time cause the medkit takes a while and the enemy shocked me again so I died.
6) Seeker mine should follow the enemies without me telling to the seeker which enemy.

I liked all the other changes, the gameplay, running over objectives and jumping walls feels very smooth and the way we shoot also feels smooth.