1.When I look at a maple I first consider the best base and nebari.
Nebari is not visible but the best base is in the first picture I believe.
2. I then give consideration to trunk line, Looking for best movement and direction from viewer.
In this case I prefer the movement on the left picture as well even though the tree is moving away from the viewer in the middle of the design.
3. I then look at the internode length and thickness of branching for placement in the design. In this case the internode length becomes longer and thicker in the upper portion of the design than will give a balanced picture. keeping in mind that trunk should taper, branches should taper and internodes should grow shorter as one progresses up the tree.
4. This is good material to work with and can be developed very nicely in a relatively short period of time. 5-10 years.
5. That being said, the key will be to cut back some overly thick branches, remove some branches and introduce some taper and movement to the upper 1/3 of the design.
6. Working simply on the smaller branching with the current foundation will not improve the tree very much in my opinion!
Bonsai is by definition an artistic endeavor, therefore principles of aesthetics are important, not just what is a natural growth pattern in maples.
7. I would choose either a short powerful tree or bigger design with this material . If the short powerful version than I would airliner off two or three portions to develop later. Design branching would one from thread grafting, allowing one to pick points and angles for branching, control internode and taper as well.
8. I marked the starting point for these two options and branches I would remove. Forgot to mark the bottom left branch, it needs shortening or replacement.
9. In both cases the new apex would be from new shoots selected to add movement and comes towards the viewer when developed.
Now you have a range of opinions to consider
I know this is brief and without a lot of detail. so questions are welcome.