I agree with eventually chopping the top. I'd let it grow out first. The foliage is sparse. I'd get it nice and vigorous at least into mid-summer, or even let it grow out a couple years to thicken. Chopping now, I don't know if you'd get the response your after (back budding).
I was thinking this when I first saw this thread, and came back to edit my post when I saw your thread from last year about insect damage. I think the soil looks like it holds way more water than what I'd use even for my most water-loving plants. It doesn't list your location - if your in Florida or somewhere hot and the tree is outdoor year round, it might be ok, but I'd go with something like pumice to protect the tree from similar damage to the first thread. That's what I'd do before considering pruning - repot when night temps are consistently warm.