The State of Thunderlord's Decree [MyOpinion]

Ok, pretty much everyone has seen this mastery run rampant. You join into games where 50-80% of players have it... Its bound to get nerfed like most other masteries have. But honestly... its fairly balanced...

Now wait....

If its so balenced, why is everyone taking it... this is were "my opinion" comes in. First lets look at what it does, though im sure most of you know:

"Hitting an enemy champion with an ability (ability damage) or basic attack (on-hit) marks them with Thunderlord's Decree for 5 seconds. At 3 stacks, the target takes 10 - 180 (based on level) + (30% bonus AD) + (10% AP) magic damage. Thunderlord's Decree can only be triggered once every 20 seconds."

The scalings arnt too bad... fairy low, like a passive mastery should be. Then why is everyone doing it? Its free damage thats easily accessible. All it takes is 3 autos/spells to trigger... and most champions can do that easily. Also, since a good majority of Keystones have been nerfed, its one of the best options...

So heres my thought... instead of 3 autos/spells, how about...

After gaining 5 Stacks of Thunderlords, it deals its damage:

-Auto attack gives 1 stack -Spells gives 2 stacks

This makes it slightly less accessible to most champions, which might be what it needs.

These are just my thoughts on it... it needs to be toned down somehow...