I like the system but I agree it is to short. They could just make it longer or maybe add a series of gems that will increase the time for different item types (also add recipes to combine multiple types into one gem). Melee would get a clear advantage since they would have essentially a free gem slot but they could offset this by building in filters into the gems. Meaning if you are wearing a gem of magic quality then it would extend the timer by 0.5 seconds (times gem level) for magic quality items AND filter out anything below magic quality so you would need to hold a key to see items below magic quality.
If wearing a gem of magic quality and a gem of rare quality then it would filter out below magic quality but if ONLY wearing a gem of rare quality then it would filter out all items below rare quality. Throw in some expensive recipes to combine these gems into magic/rare/unique all in one gems and there you go.
Thumbs up/down?
Edit: There could also be gems that filter out items based on # of sockets, socket types, links, types of items dropped, maps, gems, etc. Could build a whole gem system around this.