One change for DRK: Darkside increases attack speed instead of damage

[Reynhart]

you don't even have to manage your Beast gauge as long as you're not being above 50 whenever you hit Infuriate.

You don't have to watch your gauge as a DRK, just build 50, spend 50. You don't have any oGCD that could interfere with how you spend Blood. As for MP, in the end, it's used solely to maintain Darkside, so the only "management" to do is not overcapping.

Look at MCH, it's a one combo job, yet people are calling it super busy and fun. Look at BRD, no combo at all. And they're physical DPS jobs.

Yes, because those two have much more things to manage than DRK, with procs, skills that synergize with each other, building your gauge to your desired sweet spot and not simply to a specific value.