I just finished my first event using DT Register and to put it simply - It is a tremendously useful extension! Though the incredible functionality can seem overwhelming because you have so many configuration choices - it's well worth the exercise of setting up the event just right.
That said, I would love to see more functionality and/or option with regard to emailing registrants. Luckily my first even only involved sending out one email to remind them of the event and for those that hadn't to pay by a certain due date.
The kind of thing that would be helpful with regard to the "Email Registrants" part is
> Ability to save emails (maybe as templates) for future use
> Ability to post-date the sending of emails automatically
> Ability to send emails to specific registrants only (for example, those who choose to pay later might need to get reminder to pay emails)
I looked at your post with interest because I too want email options. I found that it was easy to export the registrants via CSV Export into a excel Spread then send mass mail from there to any combination I chose.
I am trying to find a way to set up a Kunena forum thread about each event then subscribe every member of a event to the thread. this will allow the host of an event and the registrants to keep up with announcements, question , answers and event hype. the thread is also viewable to everyone who wants to look at the hype and user generated content. the thread become a catalog of event details and can be cropped to maintain good data.
One other advantage of using the Kunena forum is on a Camping club like my site the events are run by hosts and I dont like to give out registrants email addresses to hosts. A kunena forum will do the sending without revealing the member private emails to other host and members. When I give a list of registrants emails out to a event host I send a Youtube video on BCC which no one ever watches and I always get an email with the To:field full of every registrants email. Big problem when you want to protect members from spam and the like.
I link Jomsocial group members to be automatic subscribers on individual Kunena Forums via a component called JS G-Kunena I asked the developer if there was a way to manually link a DTRegister registrant to a forum. I must note that for some reason JS G seems to make my Kunena Submit button crank slow to a completion on a forum as it subscribes group members. this has proven to be a problem with anxious posters making repeated submit attempts causing repeat email sending thru the forum