The issue is that it's random, and we already have cards like Wildest Dreams, Long Rest, and Harness Infinity in the format, none of which see meaningful play
Summer Bloom Summer Bloom is a very impactful ramp spell when played at the right time
This basically turns Grimgrin into a very large kill spell that will probably beat whoever youre attacking down in a couple of turns
Mana Cost : The resources you will need to spend to cast the spell: in this case, two black mana (the skull symbol) and three mana of any color
The design team buckled down and came up with some great themes, and the development team made those themes really work
These are also win conditions in control decks, and they fight sorcery speed sweepers very well