Mono-green ramp decks are often short ways to draw cards while still beating face, so I expect Lifeblood Hydra to become a $2-$3 format staple
A 3-mana 6/6 is strong, though it comes with a dire downside as exiling two cards from your bin is a hefty cost
As you might imagine this can get out of hand pretty fast
The early attempts varied widely between way too strong and way too weak, but no that they have learned not to make these designs to fancy, these cards have become a basic component of blacks abilities
If your opponents deck can curve Longtusk Cub into Whirler Virtuoso into Glorybringer, you cannot reasonably expect to match them threat for threat every turn
Overall) - Future Sight with a shout out to One with the Multiverse Next is this five-cost hard to cast enchantment that was so good it dominated the era of things like Five Color even though it was harder to cast there but was valued alongside Mirari's Wake as the best option to drop for free from an Academy Rector or in power