By throwing down a blanket -2/-2 on your opponents creatures, you can reliably wipe out plenty of creatures as soon as Elesh Norn enters the battlefield
Part of what makes Kalamax, the Stormsire and the Temur Spells deck so upgradable is that as long as it is an instant, it's probably decent in your deck, so you have tons of options and flexibility since instants have been around as long as the game of Magic has
There's already a good Red Madness deck in Historic, and I'm sure Anje's Ravager could find other homes as well
A slightly restricted Demonic Tutor paired with a Natures Spiral is an incredibly solid effect at 4 CMC, and even if you arent able to get the correct colors of mana to pay for the Entomb effect, youre still breaking even in terms of your benefit to mana ratio
There's some real possibility to this card, especially since it helps fix some of the issues Dredge can have, which is milling your mana resources