Arena metas move fast, especially after new sets, bans, balance changes, and major events
If you just have some traditional top end it is still a huge value and tempo swing and still has great odds on winning the game
There are so many great X spells and other outlets for a card like this one, and it even synergizes with Urborg, Tomb of Yawgmoth to create mana with any land
The transformed Sephiroth is a 5/5 Avatar Nightmare Angel with Flying, and whenever he attacks, you can sacrifice any number of creatures and draw that many cards
Aether Chaser has First Strike and "When Aether Chaser enters the battlefield, you get two energy counters"
In 2011, however, it found itself on the original Modern ban list when the format debuted, and it would stay there for nearly 15 years