Challenging (or better, complex) content comes always after simple content in the development of a MMORPG, because in the first months the battle system gets always honed/finalyzed/rebalanced the most, and simple content works much better as "one size fits all".

It worked like that in FFXI, it works like that in FFXIV, it works like that in basically any and every MMORPG out there.

Otherwise you get "challenging" content like the initial raid bosses from Age of Conan, that were released right off the bat with relatively complex combat mechanics, and ended up being extensively exploitable and bugged to hell for several months after release. From being oneshotted by a certain skill, to changes in the battle systems that completely nulled the challenge for a while, and tens of glitches that made them absolutely unenjoyable and easymode.