There is a reason why those crossover events were only temporary and most specifically will not be coming back, and that was because the whole point of the crossovers in the first place was to celebrate certain milestones being reached in those specific games (the FFXI events were to celebrate FFXI's eleventh anniversary of service for the Shantotto event and the official winding up of it's storyline with the Rhapsodies of Vana'diel storyline with that story's main character Iroha respectively; and the FFXIII event was to coincide with the then current release of the second FFXIII sequel: Lightning Returns ~ FFXIII. Likewise the Dragon Quest event was to celebrate DQX's first anniversary of service.).

Hence because all these milestones are long since past, there is no reason to run them, and with the adding of the items they rewarded to the Mogstation, it's pretty conclusive those events are gone and never coming back (it's the same reason you will never see the special events that were run in 1.0 to coincide with the Calamity return, it would invalidate their very reason to be run originally in the first place).