If they can do a temporary one for an expansion to test it out them im all for it, I do think going past 100 in levels becomes a turn off for new players but since FFXIV is very much a story based game as well as an MMO they can't just level squash without reworking the exp gain from old expansions.
So yeah experiment with it for an expansion to see if they can actually do it good first, then we go from there.