Well there are certainly a lot of claims being made in this thread about why we do things. To start off just reiterating what we've said about modding in Warhammer:
Let's move on to some of the claims made, and in particular the idea that we've deliberately made games on the TW3 engine for difficult to mod and we're holding back all our tools for no reason. It shouldn't need to be said but this isn't true in the slightest.
Modding has become more complicated on TW3, but then making the games has too as our engine has evolved and technology improved. In Rome and Medieval II you could make campaign maps from some .tga and text files. In Shogun 2, for which we released campaign editing tools, it was created via a complicated 3d model that provided multiple layers of information which was then processed through the game and combined with information from the games database to produce the final campaign.
Before the Shogun 2 Assembly Kit the only mod tool we'd ever released for our games was the unpacker for Medieval II, and that just gave access to the files shipped with the game, it didn't allow any editing of them by itself. That fell to community tools and programs like notepad, photoshop, 3dsmax etc.
Another point to be made is that no we can't just release the tools we have. Some rely on 3rd party programs, and the ones that don't aren't designed to work with the released game, because that's not the data we work with when we're making it.
We work with what we call raw data, the basic max or photoshop files for models and textures, or the raw xml tables for the database. We then modify them via tools, both internal and 3rd party, and then convert them into the format the game uses when it runs. We do this because it allows for us to work in the most flexible way, and makes sure the data we include for the final is only what's needed. The raw data for animations runs into the hundreds of GBs, in the final game the animations pack for Attila is under 200 MB.
Back in the Rome I and Medieval II days, the conversion between raw and working data was often done when the game was run. It was possible because of the smaller number of files that needed to be converted. Nowadays if we did that the game would take a few days to load up. It's not feasible any more.
Every tool we've released to the community we've had to modify extensively to work with the released version of the game. That's always going to be true with how we work.
We want to support modders, its why we release mod tools and have Steam Workshop support in our most recent games. As the quote above explains we can't do that for Warhammer, but for future historical titles we plan to continue supporting modding.
There is no evil conspiracy to block modding to try and sell more DLCs or for any other reason. I can tell you that one of the most common mods for Empire were unit packs, and the unit packs we made sold just fine. Our games have got more complex, and how we and our tools work have changed in the almost decade since Medieval II was released. That's all.
Hope that clears up a few things