While this doesnt provide a whole lot in the way of information about what the drop entails, we have a couple of threads to go off that can guide speculation
Moonmist represents the biggest blowout potential of the bunch, potentially enabling a bunch of transform triggers but at a minimum turning your creatures into their most-dangerous side right before you untap
Paying into X plus three mana always seemed like a hard sell to me when every mana counted, and drawing 1 card for 4 mana never seemed very good
This commander is a free storm trigger, a free way to get cards like Mox Amber online, and a way to give players protection with cards like Fierce Guardianship
Frequently Asked Questions What affects the value of Hurricane
Each Standard expansion typically brings 200 to 300 new cards, and supplemental products pile on even more throughout the year