DLC Ideas:

1. More loot items and better assignment based on level of difficulty of the lair.

2. Sets of loot items that add bonuses when more than 1 item is equipted and even more bonus when all equipted.    These would be rare and found scattered in various lairs.   

3. Tie level of loot items to game world difficulty level (the harder the game the better the loot).

3. More monster types.

4. After a long wait tiem, New monster lairs would appear in areas that had been cleared 

Complex quests.  Monsters with new models.  Items/Weapons/Armor with new models.

Stuff that's hard (or impossible) for modders to make.

Things that would probably make sense as DLC:

- Monsters pack

- NPCs / Heroes pack

- Items pack (Including the combo artifacts mentioned)

- Quests pack

- Random events pack

- Complex scenarios (in the style of HoMM)

- Stamps/ wildlands pack

A DLC could combine two or more of those items.

Things that would probably be bad received as DLC (those belong more to an expansion):

- New factions

- New city buildings

- New techs

- New skills/abilities.

- New resources

Summarizing, anything that adds deep and variety to the game is welcomed, while anything that makes the game feel "incomplete" without the DLC would be bad.

I think that is also more of a Expansion thing. To do it right you would need new items, monsters, mechanics, goodie huts, resources, traits, and more.

I think the best DLC would be a quest pack that added some long deep quests with some new unique rewards like new spells, items, and units.

I'm all for spells and items and quests.

Anything that makes the RPGness of this game even more RPGness!

I, for one, like the "CHAMPION MARRIAGE/CHILDREN/DYNASTY" (caps in original, sorry) idea.  Marriages often tied groups together, or caused rifts.  Perhaps they could be introduced via a modified 'henchmen' mechanic?  Some might really be spying for the lineage of one parent against the other, some provide positive and negative affects on the settlements in which they reside, come with a troop (military) retainers, or modify the like/dislike factors between the sovereigns.   Perhaps, occasionally, one becomes very popular, and the specter of civil war comes to visit.