Be carefull defoliating, certainly if you now do a root reduction. In general, defoliation is only done in the more final stages of tree development. In most cases, thinning of the canopy, removing the largests leaves is much better for the trees health, and the densification of the canopy. Leaves will reduce as the canopy gets denser and the rootball smaller.
If I judge the situation right from your post, your tree is not in a state that you want to reduce foliage mass drastically.