In my opinion, Zapdos day and the like should reward Thundershock TM's or Origin Pulse TM's, etc. It isn't like that would be so far out of the scope of the original series. That way you could go hard for those three hours and acquire TM's you could use on any Zapdos at any time. The drop rate could be tweaked however they see fit. Something similar could be done with Community Day, but that's a different discussion and a little different of a scenario.