Looks like 'microcarpa' nothing will really happen. Just turn back into a shrub over time till it outgrows the pot then it will become 'microdeadia ficus'.
They look best as a 'Banyan' or 'broom' style, you can pull a lot of pics of those styles on the web.

Bob

As the branch extends, it will continue to lay down layers of cells in the cambium, which will cause it to fatten, and lignify (become woody) with age. The simple fact that you neglected pruning won't cause the branch OR the tree to die, unless the natural apical dominance of the upper branches (only in apically dominant trees,k of course - like most Ficus [F. pumila and a few others excluded]) causes them to grow with more vigor so they shade out and weaken the lower branches, which COULD eventually cause them to die.

When we begin to move beyond the more radical steps we take to train our young trees and get to the point we feel we'd like to display them in a bonsai pot, we need to take steps to keep our trees compact and 'believable'. By 'believable', I'm referring to the idea that bonsai need to have their foliage masses positioned in arrangements proportional to where they might be located on your tree's counterpart as it's found in nature. By not pruning, we are, in almost all cases, sure to destroy the proportion and the natural look we strive for in the presentation our composition. When this occurs, the debate about whether you have a bonsai, are building a bonsai, or just maintaining an unkempt planting in a bonsai pot begins.

Al