That's not "some of your customers might complain" territory, it's "your business failed because nobody signed up" territory.
2FA basically ensures security via a second channel, and it's perfectly possible to store passwords in a secure format. I'm not convinced your ideas there are worth the cost.
2FA basically ensures security via a second channel, and it's perfectly possible to store passwords in a secure format. I'm not convinced your ideas there are worth the cost.