The skills feel a lot more balanced which is nice. There is also two types of matches now. The first type is quick matches which is like how the game originally was where you level up then put points into skills as the match goes on and at the start of the match everyone starts at level 10. The second type is permanent matches which use a level which goes up slowly as you play and it stays between games. If you played back when it basically switched to just that for a while then any levels you got then probably are still on your character.
Another thing is that the netcode is improved. The only time I have experienced any kind of lag related annoyance was when I was uploading a video at the same time and the ping was definitely above 300. Even with servers in England and other such far off places (I live in America) have good ping for me, sub 100 most of the time, that even when they are on those servers I can have a good time.
Finally there is a new gamemode. Its a zombie thing where it is basically a PvE sort of thing. Each map has bombs at various locations and the way you set them off is by filling them one by one with a thousand zombie souls each. In a quick match the way you get experience is by returning the souls to the bomb. Also the zombies comes in waves and start when people have touched the next bomb. Once you complete the first way when the wave is called everyone gets rooted for a short amount of time and the only way to survive that is if you are with the others and you all work together, though I assume if you pick a really good hiding spot you might be able to survive.