It's better to equip gear same or lower than your rank than higher. Although some higher gear offers like +2-5 more of the stats but if you're a new player the cost to get it repaired will be hard. Like for crafting if you equip higher rank tool I noticed the stats isn't good compared to tool of same level, sometimes gets worse stats. I haven't gone checking every gear to test it. I just get too lazy switching gear sometimes when switching class not really looking too much into stats. I think SE was planning to add more specific gears, maybe was only for class/job and not rank/level, pretty sure they also have something in mind and know it needs to be fixed.