I think too many modders don't make an effort to do a proper tutorial, or at least something to get others going in the right direction.
A good example is stadium editing. This could be a huge motivation for modders to learn and get into it by editing stadiums. Its been done, but I havent found one single tutorial to get a good jump on it.
I can open stadium files and view the art in texture editor, but its so confusing to know where to begin.
The reason is probably that their are only 1 or 2 modders that have ever done stadiums, so they may not have the time to do tutorials or just dont feel the need to.
this is not drag on them, since they have done amazing work, but im just stating a fact of what i think could be a reason for not many other modders catching on.