Green has been good for so long, I wouldnt be surprised if most of todays players didnt realize that green was famously considered the weakest color by a large margin in the early days of competitive Magic, a reputation that persisted for many years
Its preferred targets are ones with strong ETBs or death triggers, like Protean Hulk and Worldspine Wurm
Esika, God of the Tree/The Prismatic Bridge: Five-colour supreme
That saboteur ability is hardly synergistic with its high mana cost and lack of evasion
To turn it into a win condition, just add Blood Artist or Vein Rippereach sacrifice drains your opponents, letting you control the board while chipping away at your opponents life totals
In a blog, Mark Rosewater, lead designer on the game, said that it is counter-intuitive to have the Ring bring in-game positive effects, but it was the only way to get players to actually interact with it