I don't have the foggiest idea about Systema , but I do know Wing Chun.
The main thing that stands out to me is the lack of what we call "The Optimum Angle" or "Ultimate Angle"
The arms will roughly be in this angle all the time except when striking , the angle will contract slightly to yield under pressure when the arms are relaxed , but by and large they will generally be in this fixed angle.
It is thought to be the best angle for both attack and defence.
He seems to have dispensed with that concept along with the centerline and also opted for techniques with maybe a bit more flash but are indirect , instead of using more basic techniques that are simple and will get the job done a lot quicker with better economy.
In short he has thrown out the rules because he has been training a long time , and against low level students he can get away with it.
He would run into big problems and have to adjust his game if he were up against somebody with a decent stance , good "Forward Force", somebody who adheres to centerline theory.
They only need a slight gap to get through and then it's all over , and some of those techniques he was using allowed the centerline to be undefended.
Just to clarify , there are no "Pre - Movements in Wing Chun , nothing is telegraphed , that is a major no no.
There are no preparation movements before any attack is launched , it is just launched.
One of the purposes of Chi Sau practice is to eliminate telegraphing by only having "Forward Force.
Most Wing Chun people will work long and hard to get rid of even the slightest drawing back of the arm prior to striking .
Similarly with kicking , many hours of leg raising exercises have to practiced in order to be able to kick from the stance in a relaxed fashion without any telegraphic movement from the upper body , namely the shoulders.