Obsidian's Josh Sawyer (no relation to Tom Sawyer) recently spoke in a session at the Paris GDC. Discussing their follow-up to Bioware's incredibly popular Neverwinter Nights, the discussed one of the major things they did wrong: making the tools too complex. From Josh Sawyer's seminar:

BioWare's approach to the Neverwinter Nights toolset was to go for ease-of-use, so that people could get small things running quickly and then expand from there. Obsidian's approach was to cater for the hardcore, though - dramatically increase the level of control, meaning that more things could be altered. That would make the barrier to entry higher, but we thought that would similarly raise the quality of what was produced.

You can only get so far as an amateur designer if the tools given to you are so complex that they require far more investment of time than you can put in.