I'm doing the same. I'm leveling a group from level 1 and I want to complete all the LDoN themes while progressing through the "Hero's Journey" quest line. From the research I did, I would say YES, it's worth doing to get the vendor points to spend on some augs. Specifically, there is a 35 AC aug which was already mentioned, but also a 10 AC aug that is NOT LORE, so you can have multiples. Considering that you can start purchasing these augs at relatively low level, I think it's worth investing in. More importantly, there are some weapon augs available from LDoN vendors that proc 150 DDs. Again, considering the level that you can acquire these and how useful damage augs are before they are rendered obsolete, I'd say it's worth the effort. The downside is that you need to complete a lot of missions to accrue the points. I plan to complete all 4 themes, but it's really up to you if you think the time is worth the points to purchase the augs.