Add higher tier Unchained Solo Quests that reward T4 Relics. Reason is that there is nothing to do to advance your character except Raid Finder or Raids now. The Rare Tokens rewarded by the Unchained Solo quests can only be used for lower grade gear than what is offered by Raid Finder so no reason to do them anymore.
You could really just add a new layer of difficulty to the old Unchained Solo quests so we have something fun to do that advances our characters. Or make some new ones if there is time for that.
Alternatively you could create a higher level of rewards for Rare Tokens. I just want something to do to have fun with my character that also advances my character somehow.