About the new soldier classes:
(In case you don't know, the new XCOM has a class system. Each soldier has now a preset role and preset abilities. For example, there is the "heavy" which can use rocket launchers, the "support" which can heal others, the "sniper" which does exactly that, etc.)
Not sure I like that there are soldier classes now. In the original game specializing your individual soldiers was limited to what they were carrying. Other than that every soldier was equal (aside from the randomized stats with which they were born, ofc). On one side, the new system involves a lot more strategy, but it is also very limiting. In the original game, if my guy carrying medikits was killed, I could walk to his corpse with another soldier, pick up the medikit, and he was able to heal other just as effectively as the other guy. Or if I killed an alien who was using a rocket launcher, I could go to its corpse, pick up the weapon, and use it just fine. Picking up stuff and having an inventory gave you a ton of flexibility. However, with the new classes there will be a lot more strategy involved in "who does what", so that's quite appealing. So yeah, it has both pluses and minuses, I think.
PS: from the way base building works now, I assume Aliens attacking your bases is no longer a thing. That was an awesome part of the original game that will be missed