How to make FFXIV like Monster Hunter:

1. Take away health bars.

2. Make all monsters 3X bigger.

3. Add Flashbombs (and then call anyone who uses them a cheater).

On-topic though:

On the topic of armor, I'd rather they stick with a large variety of armor tailored to different classes as opposed to MH's philosophy of "All melee, here's an armor type. All gunners, here's an armor type." I do like the gemming concept, though it's much older than Monster Hunter lol. I would LOVE to make armor that resembled a certain creature it's made out of though, like an Ureaus or Dodore set

As far as the quests go, they could add such a system and make it something entirely new. Kind of like guild leves but you fight one big monster that takes at least 20 minutes to down.

FFXIV has a different philosophy as far as time goes. Take Ureaus for example. Instead of making the fight extremely hard and a test of endurance, it's practically limited to doing as much damage as possible in under half an hour. In Monster Hunter the time limit is generally 50 minutes, though 30 for things like Lao Shan and Jhen Moran. The true difficulty comes in a test of endurance lasting at least 20 minutes, probably closer to 40 if your team is under-geared and it's their first time.