RonMartin(deceased)

Doesn't seem like you are getting much help at all. A few terse comments but not much help.
I hate to say it but you might just like what they have said better than what I am about to say.
No meanness just a statement of fact about you plant. And mind you I might be wrong. I only have your picture to go by.
From what I can see of the picture that you have posted you have what is commonly called a "Ficus too little". ( actually the sp. name is ficus benjimina 'princess marsha' ) If it came from Brussels's Bonsai then it is called a Brussel sprout. Different nurseries call it by a different name. An easy way to get around a plant patent ;o(
Doesn't matter what name it goes by it is all the same tree.
At one time it did have high hopes of becoming the next big thing in ficus bonsai. But then it was found that as the tree aged a bit it did exactly what you are experiencing.
Branches for some reason will stop producing. The foliage looses its compactness.
I am afraid that you are stuck with what you have. It certainty wont get any better but on the good side it probably wont get any worse.
Usually if you feed it with a high nitrogen fertilizer it will help. You will regain some foliage.
But , and I do hate to say it, you might just be a bit happier if you just relegated it to a house plant status.
Sorry to be so negative. I am not usually such a spoil sport. Just in this case I had no choice. Hope you understand my motives. They aren't mean spirited.
Sorry