raghavnuckched
Emails are required for Users and Agents as this is the unique identifier for both. You can customize the code to accomplish this however it will require quite a bit of changes and you'll have to keep re-applying/maintain these mods every time you upgrade.
As far as allowing multiple tickets for 1 email address you can already do so. Once anyone creates a Ticket a Guest User account is created associated with their email and any tickets with that user email will be associated with that User Account. You can set an Open Ticket limit but this is typically disabled for most instances.
Cheers.
