DLCs

JohnnyQuantum

Regarding the Dark Brotherhood and the Thieves Guild, as I have no interest in the whole assassination or thievery theme, these DLCs have no appeal from a lore/story/character... perspective.

But, are there other reasons to make it worthwhile doing them? Game-play benefits? I've had a quick look at the skills, and nothing really appeals. Anything else...

wayfarerx

Well if you're not interested in thievery / assassination gameplay you probably won't find much in these DLCs.

Thieves Guild has the MoL trial included, so if you want to run trials you might want that one.

Both of the skill lines have some decent passives but nothing to write home about.

The delves and world bosses are pretty good.

But these DLCs are pretty small and, if you're not into joining those guilds for gameplay or nostalgia reasons, they probably don't have much to offer you.