Having him be more relevant and value generating in turn makes his hardiness more rewarding too
It goes down in value the more likely it is to get blocked, removed, or even worse traded off in a double block for a single Tarmogoyf or something
Casting a spell for 6 mana and getting a bonus 4- or 5-mana spell is awesome, but it means that you cant use as many cheap cards in your deck, lest you cascade from an 8-mana spell to a 1-mana spell
While it's likely not bannable good, I expect it will see a lot of play in the formatcards that can tap for multiple mana each turn tend to be good in Commanderand it may end up being one of the most played of the partner generals
Honorable Mentions: Crib Swap and Unexpectedly Absent Two (or probably more) c ards shouldnt go unmentioned here , and thats Crib Swap and Unexpectedly Absent
Could Be Fun : These commanders are powerful and dont pull you in a single direction, but because of that, it allows you to build weird strategies with a powerful engine