I know this was changed sometime in cata but I was recently thinking about it on my scribe.
Do you like that you only have to buy glyphs once? Or was it better when you had to buy one each time you wanted to change? What I'm getting at is that you have to buy new enchants and gems for each upgrade, but only buying glyphs once, thus leaving us scribes with lower income. And whenever you need to change glyph you'll only have to spend 50s on a vendor sold item.
What if gems and enchants were re-useable? That you could remove them from the weapon/armor when you were done with it, and put it on a new one.
Or, if tome of clear mind/vanishing powder only could be made by scribes and giving them something more to sell.
edit should be a poll with some options