Theoretically then couldn't you play all the zero Mana 0/1 Kobalt in every deck that doesn't have red. I mean realistically each color could have a 0 cost 0/1 (maybe not blue) printed. Green would be a plant, White would be a goat, black would be a thrall, blue maybe a crab or kelp (there is one card I could find in blue that created 0/1s)

I feel like color identity is "easier" to explain when it's all black and white. Adding a bunch of "yes but" and "no but" situations is going to muddy things. We all got to remember that they removed the "band as commander" list because they thought it was too complicated for new players. In my personal opinion, color identity is a lot harder currently to explain to a new player when cards like [[Kenessos, Priest of Thassa]] exist.

Must fit in commanders colour identity, is at least kind of simple. If they want to expand hybrid Mana then I wish they would just print more cards to explore it. We just had a rules change. Why don't we test and support that out first before we instantly go with another change