Color complexity Magics five colors (white, blue, black, red, and green) have always been roughly balanced in terms of how many cards each gets
While a 5-mana 4/4 isnt good, making your opponents pay a significant tax any time they cast an instant or sorcery otherwise you get a copy of it for yourself can be pretty backbreaking
Best Counterspell Enablers and Payoffs Cards that reduce the cost of your counterspells are always a boon and can catch people unaware that you had the capability of countering something
Commanders like Lord Windgrace and Titania, Protector of Argoth can do a lot with this
1: Day of Black Sun [[Day of Black Sun]] is my first pick and for good reason
The creature part is not the pull, but adds some meaningful extra value to the card.