It took me a long time to think about the idea of hybrid mana in commander, because there are so many points that are valid against it. But I will say right off the top, that I am FOR the change, but after much thought, realize that it would require a rewrite of the color identity rules in commander.
So to begin, commander has a ruleset for color identity that says if a card is a color, or has a mana pip of a color on it, then that is the cards color identity. Now this does not count color words (such as Protection from Blue does not make the card a blue color identity), and it does not count rules explanation (the thing in parenthesis on the card explaining the rule).
And here is where we come across an issue with color identity that I already experience with casual players in commander, that people use as an argument against hybrid mana: Color words make players think that a card is that color identity when that is not the case. Especially true since you have white cards that can make blue tokens, etc. So the color rules are already confusing enough for that.
The rules text exclusion also causes some confusion for people, such as for rules explanations for extort.
Complexity of the rules aren't really an issue in this case. The game is complicated. People will learn.
Next is intuition of color identity. Color identity occurs in multiple locations on a card. One is using color words: This card is all colors, This card is Red. This fills in the confusion stated earlier with casuals. Not only that, the Devoid mechanic makes a card colorless for the purpose of things like Pyroblast, but not for color identity.
Next is the mana symbols on the casting cost of the card. This one is the easiest to understand and the one where hybrid mana is having its conversation on. This also includes the mana pips on the card text. If we just took the proposed hybrid rules change and only focused on this, then yes, the proposal would work with no issues. But there are more rules to color identity which causes issue with ONLY changing this rule.
Then there are color pip identifiers on the type line (such as on the back side of Archangel Avacyn, Avacyn the Purifier) and the border of the card. This one is huge because the card itself has NOTHING else saying that it is Red, other than the pip and the border of the backside. When I was first playing commander, I didn't understand why I couldn't put this in a mono-white deck. The pips are all white, and there's nothing on the front side making the card not mono-white. But this kind of card issue also has to be addressed with the hybrid mana changes. You cannot do one and then the other.
Because there's also more types of borders and colors identities, such as the border of the card, which sometimes is colorless or gold.
Gold ain't no magic color I ever heard of.
So a change would need to be made to color identity in commander, in a way that can make sense. But not matter what you do, the rules will be complicated, but it already is. Would it be more or less complicated in any way that would matter? I don't know. But it would for sure be different. So I came up with a rules change, that I would be happy with, and I'm putting it out into the aether of the internet.
Proposal
We leave the current rules of color identity for identifying the colors a commander can provide (including hybrid mana counting as both), but only look at the mana cost of the spell and the mana cost on the card text for color identity, and not on color pips in the type line, or border/color of the card, with hybrid mana being an OR in this case and not an AND.
This means that cards like Archangel Avacyn//Avacyn the Purifier is a Boros commander but can be in a mono-white deck in the 99. This means hybrid commanders are all colors in their mana symbols, but can participate in mono-color decks.
Addendum
Also, dual lands are weird in commander. The logic is that I can't run a forest in a Boros deck, but technically the Forest mana symbol is in the rules and not actually on the card (an animated forest does not lose its ability if Deadpool chooses it). So shouldn't it NOT have a green color identity? And I can run an Urborg, Tomb of Yawgmoth in my Boros deck. So, the whole thing is really.... complicated.
You can run Kormus Bell, Urborg tomb of Yawgmoth and Elesh Norn as your commander in a mono-white deck as mass land destruction, but Hybrid mana is what makes commander rules complicated? I don't think so.