From the Q&A Summary:

Quote Originally Posted by Gildrein View Post

Q: When is the revamp of the Linkshell system going to take place?
A: Since we are receiving quite a number of demands on this, I have been discussing with the Lodestone team and would like to work on it as soon as possible to improve the in-game community feature, especially in regards to Linkshells. We understand a Linkshell search is essential.

As the work on patch 1.19 has just been completed, we are now assigning priority to each task for patch 1.20 and beyond. I consider that the revamp of the Linkshell system is a must do to strengthen the in-game community for players to enjoy the game together. So, please wait a little longer.
No definite time frame given but maybe we'll get some information soon. Or even get a response about it. Will it make it into 1.21? Or will it be later than that?