I know this is pretty much "The Paul Heyman Award" now, but I'm gonna go in a different direction.
As much as I like Paul Heyman, I feel like he can overstay his welcome a bit. And his work this decade includes his runs with Curtis Axel and Ryback, both of which were forced, and his work with Cesaro which he spent just talking about Brock Lesnar (which really hurt his push more than anything else).
I'm going for William Regal. He is the perfect General Manager. He rarely makes in-person appearances, never gets personally involved in storylines, and when he makes appearances he never overstays his welcome.
And if you're gonna include Paul Heymans backstage role, well William Regal pretty much scouted everyone who went through NXT, which is more than running RAW for the last 6 months.