Nice to hear, this is your list:
Export Generated Invits (Batch) on admin side (CSV, TXT)
Invite to include a Coupon from the online store if it was activated
Manage the case when a member choose to cancel his registration (change state to DECLINED or CANCELED for example), and not showing this entry in widget for latest member invitee or in user CP tab invitations. Manage this case in Admin CP too (actually this case redirect to non existing profil with guest name).
Replace the invite code on sign up button by a string as "Sign Up Now !"
Able to manage the case when the board is offline (just a login button is present), it could be better to say "It's not possible to sign up now, please come bacl later..."
Include the limit date to register in email.
Show invitees on inviter profil (in the same manner as followers it could be great in my mind)
Add an option of being able to allow the person that are sending an invite to add a custom welcome message to the invite email that is sent if they want.
If a new registration does not have an invite code, they may instead purchase a membership (or purchase an invite code).
Able to have invitations to a higher membership level. For example, if someone registers as regular member normally, he can get be invited by another member into a type of VIP or Private member group.
Fix for when a user registers through Facebook or Twitter (or i'm assuming any other social media that is linked), they do not need an invite to join the community. This could be a problem for some
Rework/Redesign User Tab for Invit System : Add a feature to see a list of invited people on the dashboard of a user? Like a list with invited people and their email and status?
If anyone think i've missed something, tell us what
@Adriano Faria All suggest with post link
Thank you !