The strongholds are definitely underused. Besides a few followers and "The Cursed Tribe," there's not much to do. I barely ever get to go there because of more important things, and so I wish that Bethesda would highlight them more. Perhaps they do in ESO.
Bilitis wrote: And their armors look badass. Unfortunately there's only few quests to do regarding in strongholds, you can easily do a playthrough and never enter one.
Look it up how to get there. I do it
It's not hard per se to get in there, just technical. Also, strongholds are in the countryside that's why it's so easy to miss it.
Look at Windhelm, almost everyone understand the Nords/Dunmers situation in Skyrim because of the proximity. What do we know about Orcs in Skyrim? They are parias and most of them live in tribes behind walls. You can't even learn that if you don't talk to city Orcs (like Markarth's smith, the lady one) or read lore (who read in Skyrim? Except me?). Too easy to miss.