I don't know if suggestions are taken seriously or if this has been tossed out there before (I can't imagine it hasn't) but I think it would be really cool if jobs had variants. The game and lore introduce job stones but after each base job changes to the advanced version (Marauder > Warrior), the job stones kind of lose meaning. But what if they could be used to start branching out jobs into variants? It would be a fairly simple and cheap way to introduce a lot more variety into the game.

The biggest example of this I can think of is Tanks getting DPS variants. Perhaps, for example, Marauder has a Warrior stone and a Berserker stone that gives different skills. Maybe like removing all mitigation skills in favor of damage skills. This would also help in situations where players might love their characters with a tank job glam and stuff but maybe their current group doesn't need a tank. Me personally, I love everything about Gunbreaker. Unfortunately, since my extreme/savage groups tend to already have tanks picked out, I normally end up going DPS to flex. Having a DPS Gunbreaker would be the coolest thing ever imo. I think a system like this could work well, as already proven with Arcanist branching off to Summoner and Scholar.