I'm Watching the tutorial for how to use it right now, just for fun, I don't plan on doing it.

But I'm thinking that this might be a bad thing.

Sure this can be great, easy to find free mods to give an infinite amount of gameplay.
However,
This might result in some expansions problems. for example. say guy A is REALLY good with it. we'll call him john.

John makes a huge mod based on a new dragonborn showing up out of nowhere and being an evil one. 40+ hours of gameplay around a huge area. It hits the community and people go crazy for it. But turns out this was something Besthesda was planning on doing and has already put in a lot of work into it. Now a ton of people have already played the content and the DLC that bethesda would've released seems like just a copy. John had no way of knowing Bethesda was working on the same idea and now the mod is removed(maybe?) and Bethesda loses money from lower sales, or has to start over again.

What are your thoughts on this? Could this pose a problem for bethesda and the community or is it just a too far-fetched statement to ever happen? Would you still buy the content from bethesda if this happened?

Creation kit and mod forums-

http://www.gamesas.com/forum/183-skyrim-mods/
http://www.gamesas.com/forum/184-the-creation-kit/

You would have to be really talented to create something that Bethesda was planning, in both predicting and constructing it. Also while there are many excellent modders out there, you have to remember that the studio pays it's whole team of experienced developers to do what they do.

Also, 360/PS3 players would more than likely pay for it, since there is no mod support on the consoles.

This, yes for Oblivion most of the house DLC was pretty unnecessary on pc as it had thousands of house mods, however Skyrim DLC will be Fallout 3 DLC sized or larger.

Bethesda has previously released their in-house editor with Morrowind, Oblivion, Fallout 3, and Fallout New Vegas - and this was never really an issue. As Zaria has already pointed out the smaller mods for Morrowind and Oblivion had comparable fan content out around the same time, but the bigger mods didn't really have the same competition. Don't get me wrong, there have been some large and wonderfully done mods for these games, but they're usually out a fair bit after the official content arrives.

Now a team may announce a large project which turns out to be similar to an official release, but chances are this will actually work in their favor as they can build off of the additional content Bethesda releases, freeing up their resources for more unique work.