The question then is: if a planeswalker gets two of these abilities and a third, typically game ending ability, then how do we combine commons and how many to answer the question "how many commons when combined have power similar to that of a planeswalker's first and second ability?" The new format I am thinking about would group a small number of commons similar to the old ability of banding, and enable the player to use this group or band as a single card.
The power of a planeswalker revolves around being able to use one of the planeswalker abilities without having to spend additional mana. Therefore, after the casting question is answered, we need to figure out the 'during play' cost question.
Just as is the case with commander candidates, in a format that makes commons super-playable sacrificing a card that has become part of a band does not work.... I will keep thinking about this, I want to make my box of shelved commons much more playable than what it says on the card!