alright lets bring it into the new age!

FINALY got rid of ps2 in the new expansion now you can FINALY bring xi into the new age without those ps2 limits.

Keep everything prety much the same.
Add a mini map in the corner
add modern quest tools with the ! and ? icons above quest givers heads. and quest helping tools so you dont have to use a website to do this simple task anyways.
also add XP rewards for doing quests instead of just item rewards.

then put the monsters level next to their name. adjust xp so that players are fighting lower level mobs for equal amounts of xp as a VT or so BUT they are able to fight groups of monsters instead of one monster at a time. Double or triple the amount of xp needed to level to adjust for the increase of xp gain. bring in abilites to allow for better AOE tanking agro control so players arent horrified to use aoe abilities. but still keep it challenging.

lower the prices of lower level items so that lower level players have an easier time keeping up the gear to play. also reduce downtime dramaticly. id suggest something like making potions and ether crazy cheap but can only be used outside of combat so instead of resting you can just chug and in like 10-20 or maybe even 30 seconds your back up and ready

add in looking for group tools that can automaticly arrange people into groups and then allow for ways to teleport party members to the parties location. take the beast seals restrictions off of BCNM so lower level people can spam them for gear. take item requirements off of dungeons and allow them to be spammable with maybe a loot chest at the end after the boss if there isnt one already.

then lastly revamp the weapon chain skills and make solo chains and magic bursts*kind of like a rotation in WoW* and add advanced skill chains so that once you complete your solo skill chain and then they complete theirs if timed right completes a grouped skill chain. or something really cool like that. this might also require an adjustment to TP to allow for solo chains. perhaps you start at full tp and it fills back up a ton faster than currently.

almost all of that requires very minimal changes to the exsisting game but mostly adding asthetics and speed it up slightly. make it more new user friendly to breathe life back into the population. then slap a FFXIV sticker on it and bam! instant hit!