Hi Ian,
Thank you for posting your query on Microsoft Community.
By the change in sign in page, are you referring to the email and password fill textbox displaying in the middle of the page instead of right side on the page?
However, I understand that you are referring to auto fill feature available in your browser when you say "I start typing the Hotmail account to open other accounts are not listed starting with the same first letter.".
I would suggest you to enable autofill feature in your web browser. For Internet Explorer, follow the steps below.
Remember passwords and fill out web forms
http://windows.microsoft.com/en-us/internet-explorer/fill-in-forms-remember-passwords-autocomplete#ie=ie-11
Once you enable the feature, you will have to manually sign in to all the accounts. The next time you login to the account these addresses will be available by typing the first letter of the email address.
Regards,
Jesinta Rozario