Being able to drop a portal from an invite (if applicable under certain conditions or allowed to via the new instance rules) would be very useful. Seeing as the portal system is getting attention this is a good time to point it out.

Also it's not uncommon for me to find a world outside of the game, through the website or other means, and wanting to be able to invite myself and then drop a portal from that invite so i can take people with me.

Can't count the amount of times i wish i had this function for various reasons.