I have already seen people say the card is too good for Modern by making it too easy to interact with the board, while I think that slower Midrange and Control decks finally have the chance to interact with your opponent, which is the best thing which could happen to Modern in the long run
Another option to consider is bigger ramp, maybe Thran Dynamo, which takes you from 4 mana to enough to cast your Commander next turn, seems decent
This means this deck is debuting a few aesthetically unique cards beyond the Rainbow Foil centerpiece cards
or, since planeswalkers received errata to be legendary, Elspeth, Suns Champion
So if the big guy is not the right strategy, just attack suicidally, and then make an army instead
Specializing in a specific card niche helps build expertise and a loyal audience for more profitable direct sales