Trouble is difficulty is relative. Some people find different activities more challenging. I personally find ninja more challenging because I have to juggle more timers to make a decision on what I do next. (Muta, fang, DE, huton, Kassa, SA/TA, mudra). That's a lot of rolling information to constantly track on screen to mentally manage for me. For me mnk is much simpler. (Demo, tod, twin, dragon). I don't need to keep tabs on GL or positionals because positon is straight muscle memory for me and gl is just a trick or 2 at pre scripted phases (hit bombs, use tackle etc) so I don't need to expend any mental effort on it. For similar reasons I find drg absurdly easy.

Other people with better multi tasking may find ninja easy, but find the extra button pushing for movement on mnk more challenging. I find basic movement and positionals absurdly basic (probably because I played thf in ffxi for 9 years and mobs ACTUALLY spun like tops in that game and threat levels were invisible so you really had to intuit it so 14 monster prediction is child's play for me).

Your personal toolbox and skill set determines what's hard. My strengths are in mob awareness and positioning, but weak in multi tasking so I see nin as exponentially more challenging than mnk and drg as face palm easy. But that doesn't make it true for all. As long as each job has unique mechanics to manage we should stop caring what job is 'harder' and allow then to be on the similar optimal performance levels and let players gravitate to the jobs that fit them. Just because something is easy to you doesn't warrant Nerfing it and vice versa.