To do so, there would need to be a centralized or federated list of all accounts. If it was centralized it would be against federation principles. If it was federated, then anyone who sets up a server would potentially have access to all email addresses. Perhaps,more in the style of email, like @user but that would likely lead to more confusion as people would put their email and it is essentially the same information.
I do agree that log in as the opening page is not a great experience. Helping people to find an instance should be easier to filter. Rather than a list by popularity, let them know choosing by interest or location can help find relevant content and have easy to use clickable filters to do so.
To do so, there would need to be a centralized or federated list of all accounts
Why would there be? The app would just search for the domain name first (let's say "aussie.zone") and then your username (in your case "hitmyspot"). That's kinda how email works as well. What centralized database would you need to interrogate a server on login? It's no different than the current implementation, only that you do not need to remember the website first, just enter the whole username in one go.
The domain for my email is gmail.com not Aussie zone. I also cannot log in to gmail on the hotmail (outlook? )site. Perhaps you are interpreting their request to not use username and site name and instead use email, to instead use a long form Lemmy username?
That could work, but I don't know that it adds any extra layer of simplicity, but maybe that's what they meant. My interpretation is that they are saying to link your account to your email address, as that's what most other services do. Without knowing which instance you register with, there would need to be a registry. Perhaps this could be hashed in some way, but it would still be effectively public facing as any instance would need access.
Perhaps you are interpreting their request to not use username and site name and instead use email, to instead use a long form Lemmy username?
No, I was saying to use their Fediverse username and their Fediverse password. Sorry if I got misunderstood. Nothing to do with the actual email address used at signup.