I've noticed two relatively critical tradeskill items missing from merchants.
'Bottle' is not to be found on MANY merchants, none at all in misty / rivervale, and missing from I believe all in qeynos and some in freeport too. I know of places it can be found in freeport, kelethin, and neriak so misty / qeynos and possibly other cities are more important.
http://www.eqtraders.com/items/show_...r=035000000000
'Glass Shard' is missing from several vendors including the one in misty. The only place i know for sure it can be found is kaladim.
http://www.eqtraders.com/items/show_...r=035000000000