Now it seems I can't keep an edge on it at all. I haven't changed anything, and I'm the one the rest of the cooks come to to sharpen their knives.
Thoughts? Ideas? Please? Am so frustrated at this point...
A friend of mine (who also is quite formidable with sharpening) has sworn off Shun (and VG-10) knives for this problem. I have not looked deeply into this, but supposedly the VG-10 steel is extremely difficult to get a new edge on once it dulls. He allegedly sent the knives back to Shun for their lifetime sharpening warranty to no luck at restoring them to original sharpness.
I steel and touch up my Shuns on a stone regularly when they first start giving signs of dulling, and they have stayed amazingly sharp years later. Unfortunately this doesn't help your current situation but it could help you avoid it in the future.
I am no expert, but one idea I'm thinking of would be to use multiple stones of gradually increasing grit until you get to a very fine one and hope that patience and persistence may be able to help you put a new edge on this tough steel (though this may be more trouble than it is worth).
I have used Shuns for well over ten years and I have never had an issue with keeping/ maintaining, or putting a new edge on the VG-10. I have always used Japanese Waterstones instead of whetstones to do it. I use varying grits, if the blade angle needs to be redefined I start with a 400 grit, and work my way up, if it is just simple maintenance I start with a 1000 grit and move up to 5000 and end with a polishing stone of 8000 that leaves a shinny sharp mirror finish, You can literally see yourself in the reflection. Doing it this way I get an edge that is razor sharp, sharper then Shun's "factory edge" so do yourself a favor and get the waterstones