who said theres not gonna be the ability to edit models and skins?
No one, but what is posted on the blog of CA is quite vague.

You can read the whole article here http://totalwardev.blogspot.com/


But what is subject of all this debate is this :
Meshes & Textures
The final area I wanted to talk about was the mesh/texture files used for soldier and siege engine models. These are a very different format to the CAS files with which Rome modders will be familiar. Currently, modders will not be able to edit or replace these files.

This is because the format is optimised specifically for rendering. We made this decision to enable us to ramp up the level of detail of the battles while retaining a good level of performance. We are investigating options to allow the community to create their own mesh files.
It looks good but as you see they want to avoid concurency to copy them and this is were it may be problematic I think not especialy from CA but more from SEGA who knows .