Alain,
I very much admire the work you have done with root over rocks. As you know I always have a few comments
I believe a dark blue pot of the same caliper will enhance this beauty, especially in autumn.
Although extremely well displayed, I cannot go WOW, for the time being that is
To me the right hand branch is bothersome, too long giving the tree a coniferous look vice the natural (more rounded) look of a maple. By rounding off the canopy, which by the way is easily seen in your pics and easily accomplished and shortening the right main branch you will well on your way. Keep up the good work!