Originally Posted by Reynhart
First, let me say this : Horizontal progression is basically impossible as long as the the level cap is increased.
Now, if we suppose than HW kept the lvl 50 cap, horizontal progression would mean that gear obtained from the three parts of Coil, the three parts of Crystal Tower, the three parts of Alex and the two (soon three) parts of Mhach could all be relevant in a way. Of course, you wouldn't need all items from every instance for every job, but at least one item in each could still be interesting.