i really liked if someone skilled in programming (im just an old cobol programmer lol) will say this clearly:

ffxi do not use real istance like WoW and never will.
asking for dynamis istance is foolsense.

for every istance of dynamis they have to create a new zone.
ffxi have a limited number of zone they can implement and we are near the cap.
unless they totally change the way ffxi handle zone id, this will never happen.

this is why every istance-like event (nyzul, bc, mmm) have little map that can be stored in a single bigger map.