This is quite the quagmire of a discussion to start, but it is inevitable.
My
feelings are that we will not be given age creation tools from Cyan. I'll list my reasons.
1) Cyan is busy enough just trying to get new content to us they make themselves. Unless they release the tools they use in their studio (highly unlikely), they will have to build ones taking time away from developing content for MOUL.
2) There is no need for them to make them. We have many talented coders, and designers in the fan community. We already have tools to make ages (albeit they are still a bit crude), but they are already making improvements to them, and with the creation of the GOW, those projects will most likely increase in speed and usefulness.
3) If they released something that has limitless freedom, it could very well cause havoc for the Live servers if someone was inclined to do so. You would basically have a road map to how MOUL works, thus allowing you to figure out how to break it. If they make the tools to restrictive, people will either find ways to unlock the restrictions, or become uninterested as it won't allow you to do what you want. Carefully developing a happy medium would take a lot of time and planning.
4) Using fan built tools will be a big vote of trust in the content creation community. This will mend a lot of fences, believe me. If Cyan is smart, they should go this route.
Now I know many people here believe Cyan will release tools of some sort, and I don't mean to say you are wrong, I simply don't
feel that that will happen, so please do not get mad at me.
As for the kind of files they would have you use, that is a very tough question.
Lets say for this discussion Cyan plans on releasing tools.
If they show support for a program that needs to be purchased, like 3D Studio Max, they will get a lot of flack from those who can not afford that software. On the other hand, if they favor freeware like Blender, they may get some flack from those who dislike using Blender. A third option is acquiring a 3rd party creation software, adapting it to work with Uru files, and releasing that at a small price, or free. Then they could tweek it to give us as much or as little power as they want us to have.
The third option would be the best for them, but also be the longest and hardest to develop. Even using already built software would require a lot of modifying and testing. Not to mention the money it would cost for the rights to use and distribute.
They could also just release plugins for a few different programs. THat would take more time, but would probably be easier than what I explained above.