Then they should be using their own original rules system than try to use d20. If they can't adhere to the rules of an established system for whatever reason they simply SHOULD NOT USE IT AT ALL. Its not that hard to figure out.
When I run my own campaigns I use whatever rules system fits the campaign best. A balance between the importance in story and the rules system used needs to be maintained for optimal enjoyment. My campaign story has went from GURPS, to Interlock, to FUZION and now d20 System. If the rules system that Obsidian is using to tell the story of KotOR or NWN, or whatever CRPG they do in the future does not fit the rules system then either scrap the story or scrap the rules system.
KotOR1 is a rather unchallenging, predictable game though had it s good points, it had some major faults as well. These faults were because Bioware chose to change teh rules system to fit the story and not the story to the rules system. If the rules system was unfit to tell the story that they wanted, which was obvious, then they should have used an entirely new original rules system instead of a bastardization of d20.
Also I have no problems with a level 5 or 6 character after 40 hours of gameplay. Its how it should be done in the first place.