Sure, he works in other decks, but Elves is one of the decks that leverages all three of his abilities
You can watch videos of people opening sealed booster cases and boxes to verify this for yourself
Gavin Verhey noted the design team was allowed to do anything, and ultimately chose to include just one meld pairing in the entire expansion
Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel
Oh, since this list should mulligan INCREDIBLY well, how about Winds of Change
They both have the same rules text and they both do the same thing in the actual game, which, as usual, is to allow the Blue player to stop anyone else from having any fun