I do agree, but I also disagree. Having come from shooting with a little HC1 and an Ikelite housing, I reckon I got some good shots but it has serious limiting factors.
Have a look all HC1 footage
No decent WA options, crap in low light and lack of gain control are a few that come to mind. This limits the shots that you take or can use which personally I find extremely fustrating.
Now I have a Canon XHA1 in a Gates housing and it's heaps better but as you say the camera will not correct poor camera work. You can get a stunning image with low end gear in the right conditions, but if you want great images on a consistent basis you need the correct tools.
Jon