Account creation user experience/Engineering/HTMLForm

E3 has Userlogin ready to soft-launch and Create account nearly ready, but using the crufty QuickTemplate system. We're considering moving to HTMLForm.

Agora/Engineering has the engineering challenges

Deployment issues
If we deploy Tyler's change there's a big bang where login changes even if you don't pass ?useAgora=1
 * Do we soft-launch the new login form alongside the existing template?
 * Do we launch login with HTMLForm with an option to useAgora?

Tyler only changed Login, there isn't an HTMLForm version of Create account.

Reasons to move to HTMLForm

 * for consistency we want all forms to move to Agora, and most forms are made with HTMLForm. So someone will eventually do it anyway.
 * does things for us (implements CSRF? with Tyler's patch, does throttling)
 * engineering cred, acknowledge Tyler's work

Reasons not to
Greater risks, fixing core doesn't "move the needle", delay.

Getting Agora out becomes tied to getting HTMLForm changes approved.

E3 has no plans to move other forms to Agora.

Alternative

 * 1) Soft-launch current login and create account changes (that use QuickTemplate)
 * 2) Work to switch some existing high-value form made with HTMLForm to Agora style.
 * 3) Merge Tyler's login using HTMLForm together with the changes for the Agora form to use it.

But there are no great options, and the login form changes twice.