I used to main Rogue during SB and just today I got my SAM to 62.

I can tell you the job gets immediately MUCH busier at that level by having more kenki to spend, which translate to A LOT OF GCDs and mobility. And it only gets busier from there.

Also it's the only DPS I've played where you can actually notice your high DPS.

Which brings me to another point, NIN has the 'support tax' still for whatever reason. SAM will always be a full-functioning carry that gets all the party buffs.

That said, NIN is still a wonderful job to main and objectively has the best gear options.