Roofers dropped something heavy on my 7' red leaf japanese maple, snapping the trunk off at about 1" diameter as well as removing the lower branches on one side. It measures 3.5" diameter at ground level and is 15+ years old. Its branches covered about 12 feet in diameter right down to ground level. It WAS gorgeous. Now, new growth is sprouting out of the main trunk at a fork just below the upper end where it was snapped off. My question is, will this ever look like it used to, or should I have it replaced? I've been advised to prune the remaining branches way back on the undamaged side to encourage balanced new growth. Will new growth appear lower down on the damaged side where a branch was removed?

Thanks in advance for any opinions and advice!