I think the problem is uh, artists and software engineers have completely different skillsets, and work on completely different things, all the time.
I'm pretty sure its safe to say, we'll still have this many bugs, if we had 0 new artwork/models, or if we had 100 new artwork/models every single day.
Unless its something like a clipping issue or something I have enough faith in "black box" and modularity to feel that no amount (or lack thereof) of artist work is going to significantly impact programming work.
That said, you must also know the "too many cooks in the kitchen" thing where throwing (or hiring) more programmers isn't going to solve this problem either.
I have no opinion on the graphics bugs - yes they suck, but from the few courses I took on graphics programming, its hard. And oftentimes you are working with an abstruse (or obtuse...heh) graphics engine that is out of date or significantly customized and it is hard to figure out a solution without causing more problems.
Art, assets, new content, is always the scapegoat when it comes to things breaking, while 99% of the time they aren't the problem.