1) Non-combat quests. As I've posted elsewhere, there's plenty of fighting to be done in Skyrim, but not many non-violent quests. Sometimes even basic fetch-quests are more interesting than "go here, kill him, get reward". Yawn.
With the amount of dialogue you're adding, the possibilities are endless - complex murder mysteries to solve by talking to witnesses, negotiations between parties to solve a dispute - anything!
Even if it's just interactive storytelling like the old "choose-your-own-adventures" books.
There's two non-combat quests in the game now : the two minor ones. The big one does contain quite a lot of fighting (indeed, some pretty tough battles here and there!) and the next one has a single combat-related step, though both have plenty of dialogue despite this. The two minor ones can actually be failed in a number of ways so being halfway smart is pretty useful for them.
2) The game world seems very static. Once you've done everything in an area, there's not much of a reason to go back. How about adding some of the NPCs over time?
Right, some NPCs should only come out when it's a sensible scenario, and that's balance things out a bit too. Still, most NPCs here are not squat in the middle of a city so you won't just come across them every time.
The first time you go to a town, there's loads of people to speak to and loads of quests, but by the time you've returned a few times, there's nobody new and nothing new to do other than radiant quests. If you could add NPCs to a town over time (either after a set number of days, or after the player has completed a set number of vanilla quests in the town) this would help breathe more life into the game and help the game's longevity, as well as making the world seem less static. It'd be very refreshing to see someone new every now and then, giving a sense of movement to the world. I'm concerned that with this mod the world will seem overcrowded at the start, particularly for new players, but will seem even emptier once everything has been done in an area.
Given the size of the world, we aren't exactly overrunning it. This isn't wars in skyrim or such, with dozens of new ones in a single area.
Quality over quantity.
And how about adding some of the NPCs as random encounters?
What do you mean by that? Some travel so you can just come across them on the road, etc.
As for the old "Integration: The Stranded Light" mod, ironically for me the one thing it didn't do very well was to integrate into vanilla (however respectful it may have been of past games) - the characters all seemed a little "off" - and I think in the even grittier Skyrim setting, the more otherworldy or comedy NPCs might be a little jarring. That's not to say they won't have their place or their fans. And I admit the Dwemer construct does look fun! Maybe an optional esp for the more otherworldly characters?
Well, there's mostly sensible characters so far, and even the Dwemer Construct goes on about information related to the historical dwemer, while being a pretty funny guy in general. There's quite a few characters that have an amusing or interesting side to them while being completely coherent within the narrative of Skyrim.