Horizontal progression gear also made more sense in FFXI because you could swap gear mid battle, so the level 75 piece that was best for regular attacks was different from the level 75 piece that was used during a weaponskill. Also, gear affected elemental damage, so a black mage would have all 8 of the elemental staves and would switch them out to match the element of the spell you're casting.
XIV's elemental system is completely different, and while some pieces of gear do affect it defensively, none of it is affected offensively. I don't think that's a bad thing.
And even FFXI eventually caved in and let you combine all your staves into one mega rainbow staff.
