from my point of view, allowing modding means the big red stop for developing the sim from developers side. you will have mods for everything and no developer input at all. not saying I don't like the idea, I do, but as we know scawen he's really perfectionist and I doubt that he would allow to do let's say Renault Trophy mod as in rF, because the physics model is simply not realistic enough if you do the modding. yeah, 3d models might be awesome, but physics can't be done at 'home'. you have to get the data from real models and all this stuff, and i am perfectly fine with the way how lfs works without mods right now, just more content such as tracks or the long prepared VW would make a huge mile step forward in LFS as a whole.
just my 2 cents.