I use foliar feeding a lot and have found it to be very effective, producing a noticable increase in growth. Arguably, most of my feeding is foliar. I use organics from February to November, but that's mainly to maintain a healthy soil ecosystem. As most of my trees are still developing I need more than that so I foliar feed from April to September also.
I don't think I would foliar feed a tree in the refinement stage as it produces very vigorous growth, but I might use a weak solution to correct a deficiency.
I see no problem in foliar feeding after repotting (I've never had a problem with it) and gives the tree a boost when it needs it the most. It's a very efficient way of fertilizing, as long as it's done correctly.
Here's an article on
Foliar Feeding. It's quite long, but it explains the principles behind foliar feeding and presents research that has been done.