Not sure why laners would buy the supp items anyway.
Coin: You don't get the new bonus unless you collect Coin "coins" (weird,,,why not call them "bits" or something?). ANYWAY, "coins" don't drop if you are last hitting. Also keep in mind, I'm guessing the "coins" will be like Thresh souls. You still have to pick them up, so in the middle of csing and dodging, etc, you also want to be trying to grab "coins" that are littered around?
Shield: Don't know how powerful the shield is yet, bit either way, this item puts you way behind if you buy it early unless you are a tank supp anyway.
Edge: Again, don't know how much of a speed burst, prob not worth it.
Obviously, the coin is the main issue, but as I already have shown, there's no worries. AND, we still don't know what the "bounty" amount is going to be. They may have it planned that you finish the quest on avg by level 7-8. That is far enough into the game that a laner taking one of these would be SO FAR behind that the small boost from completing the quest is irrelevant except for supp.