i found that that alot of my sharp knife problem was actually how i was cutting the leather, when its laid flat on a table it becomes much harder to cut, your pushing against the leather causing it to bind on the blade plus trying to cut whatever you have under it.. I found that picking up the leather or getting some air under one side or the other makes it about a hundred times easier to cut with any knife. as far as sharpening if it can shave hair its plenty sharp. its not rocket science it just takes practice. farthest i go is 2000 grit paper for stropping if that is what you want to call it.
Heres where folks fail IMO, create the primary edge with a rough stone, sharpen it till its as sharp as you can get it. The edge will cut but feels rough, like a saw blade, then start with your finer stones working to clean up the edge until you start to get a very fine roll of metal forming. then you strop to take of that fine roll and polish the final edge. Most folks i have seen that have problems sharpening don't create that sharp edge first with the rough stone, they go into the finer stuff way to soon and are just basically polishing the side of the blade not the edge.