Rivers first ability is Meet in Reverse, which lets you draw cards from the bottom of your library instead of the top - which is funny, if nothing else
I want to say this card is good, or even great
If Gisath resolves, it will absolutely take over the game, and it has the ability to race any deck by potentially bringing multiple Dinosaurs with it when it attacks the turn you cast it
And in Bracket 5 (cEDH), its all about speed and consistencycombo decks are right at home
There are other options like Crackdown, Elspeth, Sun's Champion or Dusk / Dawn see you friend :) MrHighscore on In the grim darkness of the far future 3 years ago Maybe board list: Brainstorm Ponder Preordain Access Denied Blood Artist Elspeth, Knight-Errant Elspeth, Sun's Champion Invasion of Tolvada Flip Lightning Greaves Myrel, Shield of Argive Swiftfoot Boots Thalisse, Reverent Medium
You may exile Dragons Approach and four cards named Dragons Approach from your graveyard