This is one of the biggest cons of vertical progression: equipment of a certain level will, at some point, be rendered useless to the general player base (that being players who are moving forward and want to become stronger). In the case of XIV, this point comes every 6 months (or every 2 patches).
The other problem that XIV has is that new content that is added requires a higher item level for participation. Whilst content is generally added for all levels and play styles (i.e. story related content is of a lower level than the 3 new dungeons, which are in turn lower level than the current top tier content), in comparison to the previous content addition, the shift progressively increases. This wouldn't normally be an issue, I don't think, but the ease of access to the "baseline" equipment is too much that it renders even the recently added content practically obsolete to most players, especially those in the "I want to get stronger" camp. You don't find very many players who are gearing up using dungeons like the latest expert dungeons, or last patch's expert dungeons. It's just unnecessary to do that (outside of collecting gear for some alt classes).
That's really the main thing that needs to be "fixed". I'm all for trying to let players play catch up but it's a little ridiculous at how easy and fast that can be. For me, personally, I get more satisfaction out of earning my gear and my strength. But with the current ease of access to top tier gear, I don't feel that at all. I've kept away from the Hunts because I feel it cheapens the whole game, but as we're (the people I play with) are doing these and pushing ahead, I'm starting to feel like I'll have to in order to keep up.
tl;dr I'd rather see meaningful content, regardless of what level/tier of -core it sits at, than simply adding in more of the content that people won't want to do because there's an easier path somewhere else. (But trying to change human nature isn't something a game is going to do, without punishing the more casual players at the same time).