Is This A Reason For Leaving? No.
A guy once took up golf, he loved it and played every week, usually more than once each week.
He practiced all the time he had.
It took him ten years to get from a 28 handicap down to an 8 handicap.
But here’s the interesting part, it then took him another ten years to get from an 8 handicap down to a just a 7.
My point is this:
Just because your improvement seems to be slowing, do not mistake this for a lack of progress, or even worse, some form of personal decline in your Wing Chun.
Okay, so there may not be so many new techniques, shapes or blocks to learn, but advanced progression is refinement in the tools you have already acquired.
Others will notice the your imrovement even if you do not.