Can you go into more detail here about what you think is missing from the campaign gameplay? It has been awhile for me since I really got into a TW game a lot, and probably M2TW is the one in which I have the most experience. Aside from setting tax rates of individual settlements, I don't remember the campaign play being much more complex at all in that game. Are there specific mechanics you wish they had included from past titles into this one?
That said, I think the appeal of these titles is the battles, units, magic, etc. and not in having a campaign map with the richness of something like Europa Universalis or Crusader King. If the campaign mechanics were much more complicated in TW WH, I think it would be kind of tiresome as this is not really the primary appeal of the game for me (and most others I think).