The bump stop is there to first prevent the shock from being over compressed at full bump first and foremost, and can also be used to help with the tire rubbing at full stuff...

When you're on your bump stop, do you still have shock up-travel left? And also do you still have tire clearance to the door/flare? If you still have shock travel left AND you have tire clearance why not look at reducing the amount of bump-stop extension you are using? In this scenario moving your shock mount higher won't keep you from hitting your bump stop any sooner? If the shock is not yet bottomed out it sounds like going through the exercise of moving up the shock mount higher is kind of pointless.

As far as down-travel, if you're still on factory links there is only so much droop you'll get out of them. Going to custom, adjustable rear links with heims on both ends definitely freed up some binding and allowed to get more downtravel on mine.