Sorry to pour scorn, but I'm unconvinced as to alterations to the existing route. I know it was changed once in the past after a fatality (one of the Army guys, not a fellrunner) and some access issues, but there's an immense tradition here. Adding an extra peak (even if correct in terms of the surveyed height) would really significantly change the nature of the race. I think the fact it doesn't go to the top of any of the Glyders but crosses the ridge as a means of getting from A to B is a fairly unique element of the route. Besides the description in my Welsh 3000 Foot Peaks Book will be out of date if its changed.
On the other hand Yiannis makes a good point about the Dwr Cymru road - I spent a good part of Saturday looking down at it: must be grim to run down.
Difficult decision for the orginaisers, I think...
Jim