@blockbasis Yeah, I have worked on a couple of projects with varying solutions. One developer had proposed a username, which is similar to an email.
The issue with your platform is that you become a central entity, which is what many are trying to move away from in the space. People want to be able to possess their own money without a third party keeping the ledger (so to speak).
So, if you really want to make strides as a company, then I would recommend finding a solution that does not cause the user to entrust their funds within your platform (cold storage). One way would be assigning the email to a specific address similar to a login to any normal site. Each address has its own place in the database, which is assigned to the email. The password could then be attached to the private key.
You could keep it decentralized by using a network instead of central servers. This may help with security and hacking.
Obviously, it will be more complex than what I stated, but I could see it being more successful as a decentralized concept.