If grinding Nexus is obnoxious - don't grind it. Presuming that you're doing things the game expects, like accumulating Tomestones by running Roulettes once per day, you'll build up points as a side effect. Just make sure you do those activities on your Nexus job. DPS queues may be obnoxious, but if you're only running one or two Roulettes per day, that shouldn't get in your way.