This comment strikes home. The "bug-space" is so much smaller, and definitely possible for a lone newcomer to grasp in a day or two
You may need only a day or two to orient yourself to the source code, but that’s on top of months or years of experience with X11R6 and ICCCMv2 and EWMH and such. How much debugging did you first need to do to discover your current issue was even in dwm?
EDIT: I especially love the phrasing in Wikipedia's ICCCM article: dwm "can be configured for compliance". If 'configuration' can include editing source code, I'm sure that's true!
Dwm "wins" by just giving up, in a sense. It doesn't try to implement a taskbar, therefore it cannot have a buggy taskbar.
EDIT: I guess it does have a "Taskbar", but in a very, very limited scope.