Several of the Level 50 dungeons award Poetics as well, up to 100 per dungeon. Do 6 of those in Duty Finder and you can get 1 unidentified item.
You can get a group together and just run them quickly.
If your data center still does Frontlines, you get 50 esoterics per Frontline. At least on my data center in the evening, the queue from Frontlines is very fast.

You can also get both poetics AND esoterics from doing mob hunts. PLUS, you get allied seals, which you can also exchange for unidentified bones and shells. That's one of my favorite methods. Keep the Party Finder open and look for groups doing hunts.
I think this is the fastest and cheapest way, as long as people on your server do the hunts.

Do roulette and daily quests every day too of course.