Really don't buy this. Player characters clearly move at a slower pace, are heavier. We already know they removed the momentum building, so thats something else that is slowing down the game play, and mech dashing has been reduced across the board, again more slowing down the game play.
Another thing that makes the game look slower is actually the removal of the AI bots from many of the modes. This kept the action constant in the original, now players have long periods of no combat going on as they seek each other out. While before with the AI, there was constant warfare going around you, it helped push the illusion of battle and frantic speed of combat at all times.
Also from these previews, lot of these maps are looking quite horizontal in nature, the vertical gameplay and map design from what we are seeing is quite apparent. There is lots of open ground in these previewed maps which just further creates slower gameplay, as alot of players are shown doing ADS combat, with no where to really go for wall running, climbing, etc.
I'm really not buying the scrub argument here, it wasn't an issue with early footage of the 1st game, and we do know of how they have slown some aspects down.