Create mobile responsive landing pages and invitation emails for events

It would be nice if emails composed within events were more flexible and used the same email creation program as we use in regular email campaigns. Because I have been creating Constant Contact emails for several years, I was familiar with the old email creation program, but I have to think it is challenging to newer users.  

Also, there needs to be a way to easily send event-related emails to a select group of registrants rather than all of them (eg. late registrants who sign up after an email was sent to all who registered on time).  I figured out a work-around, but it took hours! 

Thanks!

Mary