The only thing that bothers me about DLCs are the problems they will create with modding.
If I think about an awesome mod like PDM for vicky2, I can't see it work with a DLC model :
If all the features sold in A House Divided had been sold in separated DLCs, there would have been dozens of different versions of the game because of all the different possible combinations. PDM modifies every single aspect of the game, how could it possibly adapt to that ? It would have to tweak and balance the mod to be compatible with every possible combination of DLCs and this is impossible.
With AHD coming out as an expansion the modding team is working on a new standart version of the game which is the same for the all community. They have a solid, stable base to work on and they can start a new version of the mod knowing everyone has the same game with the same mechanics.
If multiple game mechanics are added by DLCs no global mod for the game (like PDM or MM) will be possible. No mod will be abble to change every aspect of the game, you will only have small mods working with x batch of DLCs or even designed for a single DLC. The player will be confronted to this choice : either I play with mods or with DLCs. This dilemma was already present with expansions (like in HOI3 : either you play FTM or you play Semper Fi's mods) but DLCs are only going to make things worst.
I'm affraid massive DLCs will seriously limit the modding possibilities for a game. I'm not really worried about the multiplayer because PI said somewhere that if the host of a game has a DLC all other players will have it too (and that's how it works in Magicka already so I trust them) but I don't see any solution to the modding problem.
Worst than that it might even create a competition between modders and devs instead of a cooperation. A muslim DLC is asked a lot on the forums but I'm sure there will quickly be a muslim mod created, perhaps even before the DLC. The mod and the DLC will be in open competition and in my opinion it can't be good, because in that situation, PI will have interest to limit the mods to sell its DLCs .
Currently the mods are adding to the games and are making them more attractive to customers (I bought AHD mainly because the next PDM version will be on AHD), but with a DLC model the mod are just going to be open competitors of the DLCs and PI will no longer have interest to support the modding community, I don't want to see such situation.