The API should have hook functions for user login and logout and allow users to customize the standard dialogs; for example add a company logo.
Maybe you can do your own login logic, then you can do it however you want.
I like the functionality the standard dialogs provide (email approval workflow for new members, forgot password support, etc.) It would be awesome if there were hook functions to know when a user lgged/out. Currently, I have a check in my site’s onReady function, but it is inefficient because the condition is checked all the time, not just when there’s an event.
Being able to add a company logo or other text to the standard dialogs is more of a nice to have - certainly nothing I cannot live without.