I think in your adoration tirade in favor of Bethesda, you're forgetting some other, sometimes even grander, modding communities. NWN, for instance, is much better in terms of modding than any bethesda game ever was. The Gothic community is also a great example of how much a modding community can do for a game. In terms of Bethesda's games, the most important faults of games such as Morrowind or Oblivion are difficult, or almost impossible, to mod in. I don't believe Morrowind ever had a decent combat system, nor leveling system, no matter how many mods were created. I don't know if that was the case for Oblivion, because I couldn't be bothered to look for mods.
Thence I prefer Gothic III's mods, because those mods fix an incredible amount of problems you have in the game. Gothic III was a very buggy game with an intriguing premise. Oblivion wasn't buggy at all, just boring. It's hard to fix boring.
However, one does have to understand that a modding community, how great it may be, does not generate an income. Companies have to weigh the added value of a modding community against the added cost of spending time enabling it. That balance is rarely positive. Thus, in order to make a modding community possible, Larian will have to see how much work it'll take to make the game modder-friendly.
I can only agree with many things you mentioned. Following Bethesda and their games since Morrowind. One has to make a difference in the support. Actualy so far the Modd Community did not got so much support from Bethesda as it might look like. They mention many things on their blog but there was never a "official" support compared to something like a "make something Unreal Contest" from Epic which even had a few full price games as result (see Red Orchestra), or just to mention Valve with CS, DoD and a few other games in the begining (valve today is a different story).
Bethesda is definely not that modding friendly. Many things modders complain about for years are still not fixed. Not even for Fallout 3 which has exactly the same modding issues Oblivion already had. They did not even took the time to look in to that and trying to fix those issues.
