It's rather interesting to note, that only 7.4% of all players on PS3/PS4 have beat T5 (as that's the percentage of PSN FFXIV accounts that have the trophy for doing so). I'd imagine numbers for PC are pretty similar.

Given that abysmal number, is it any wonder that people want a "Story-Mode"? Coil will still be for the top 10% of players, just with that mode it lets the other 90% at least experience the lore.