I find the looping lowest branch potentially interesting, but one can easily make any new shoot do this with a little careful wiring during the growing season and/or shortly thereafter, just as with Japanese and most all maples. So, there is no reason to be in love with this particular branch. Cut back to any node and you will likely get buds at the node (or branch collar) to make new branches. So, the real question is about the trunk.
Do you like that trunk? I don't because it is straight and essentially taperless = boring. The nebari looks okay to me (for now). and there is some tapering of the trunk up to the second branch. The second branch has a relatively short internode (distance from the trunk to those first shoots), so you might consider chopping above the second branch and shortening the second branch to its first internode. You'd also want to do something similar to the left branch, likely shortening it to the point that all that sweeping curviness is gone.
The basic point, is that you'll always be stuck with the bottom on the tree. Does this basic structure
or does this
appeal to you more? Of course, you must imagine how the tree evolves or you make it evolve from here. You could make a fairly squat wide canopied tree or grow a magnificently moving and tapering trunk from here. It is hard to choose, but opting and going with what happens is, IMO, the joy of this game --> make a5 year plan, review and modify it at least annually according to what has happened and how it changes your vision.
Even if you are already clear on your choice, there is the question of whether the trunk (base now) is as thick as you want, because it isn't going to thicken much after these big cuts. You can keep that upper trunk for another season or few seasons just to thicken the lower trunk first.
That is pretty much all there is to launching and enjoyable decade or two long adventure creating a magnificent vine maple bonsai, IMHO.
