I recall that earlier versions of MindManager had email and contact map parts but they were dropped so the only way in which you can initiate an email in current versions is via the Add Link function which as you indicate don't contain any information from the topic to which the link is attached.
You can however still send emails to MM from Outlook, or initiate a query in Outlook to pull in emails into a map.
If you're using MindManager Enterprise, you should be able to send to Topic to Zapier and then have Zapier send an e-mail.
When sending Topics to someone via Mindjet Tasks they should normally receive an e-mail with some details (mostly Task Info and no Topic Notes or Hyperlinks).
Also, if you copy the Topic you should be able to paste it as a Bitmap in your e-mail client. Maybe this is something you could use?
Zapier may be able to do this but I think the ability to add the topic name to an email link without having to copy and paste it would be a simple and useful addition in its own right.
All that would be needed is a button in the current Add Link Email Address dialogue box that when clicked would paste the topic name in the Subject field.
And while we're on the subject of links, the ability to have live links actually in topic names - including email links - would be another great feature.