MOVEMENT

The main problem is that all these movement techniques are not intuitive at all to perform and they are usually automated by a even a lot of the sweats through the use of scrips and macros. 

It's one thing to have a dash or double jump or leap(revenant,vantage), that kind of mobility is part of the identity of the legend and everyone can take advantage of it, new or oldschool players alike.

The big problem is when you get this octane sliding around at mach one seemingly with no momentum loss and being able to shoot accurately all at the same time. It's just tedious and an instant turn off fighting against such players.