Bladehold War-Whip: Double Strike is awesome, and getting a reduction to equip costs is always nice
It might turn out that this card is better in Yorion-style decks, but for now, I think Green looks to be a great home for the card
Contract from Below is the most powerful card in the game if you take away the ante part
Seedborn Muse is a very powerful card, so any card that has a similar effect is likely to be very powerful, as well, even if it works only for a specific group of cards, as is the case with Murkfiend Liege, which balances its ability being more specific by making creatures more powerful
Considering that many of the serialized cards from The Brothers' War weren't great quality, it's a legitimate concern
In the context of Modern, the card is great against Hammer Time and Affinity, while also being a flexible answer to cards like Blood Moon