Originally Posted by
Gunspec
A problem with horizontal gear progression in FFXIV is that we ALREADY have severe trouble in terms of inventory management. Thanks to vertical progression, you can safely discard any gear you have replaced, unless you want to hold on to it for cosmetics.
With horizontal progression, you would need to keep multiple sets of gear to mix and match the secondary stats. For example, if they were to design gear to utilize elemental resistance for horizontal progression, you'd need at least 6 sets of gear on hand in order to fight the extreme primals in a row.
With vertical progression, you'll be using the same amount of storage space for your important gear in three years as you are using today. (Assuming classes continue falling in the general established categories.)