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
For example, every Alpha common is rarer than, say, an Unlimited Black Lotusa whopping 18,500 of those were made
For the first decade or so of their existence, not being able to attack was built into the rules of Walls, but as Magic has shown us time and time again, limitations breed creativity
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
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