Namely, most of the flashback and friends cards were created for non-commander formats, and some of the good ones are a nonbo with being copied (Echo of Eons)
While were on the topic of player experience, its worth noting that Omens add the potential for a ton of extra shuffling to a game of MTG
Not exactly, but The Unagi of Kyoshi Island does a good impression without being broken like the Game Changer sphinx
Lord of the Rings was a perfect fit for a game already so influenced by the godfather of fantasy stories, and the team took an opportunity to add their own twists to the look by not replicating pre-established representations of characters like Aragon and Arwen
We finish with the unusual uncommon in my top spot
Exiling the graveyard is one of the easiest ways to shut some decks out of the game, and its easy to play Anafenza on turn 2 with mana dorks