Hello Kevin,
open bugs alone are never the issue.
We can have millions of them open and still being able to manage things
in sanely manner.
So if the issue is not open bugs as whole, what it can be?
Open bugs for specified area. Imagine you work on KDE, you fire up your
bugzilla and start watching whats going on. Currently we have around 200
open bugs, which is manageable. But at one point we got nearly to 500
where we really lost any track of what the heck is happening.
The goal should be that projects itself should focus and try to lower
their bug count or introduce simple queries for their members to have
reduced number of the bugs in their list.
Open bugs are good, they are reminder that we should look to issues,
even if it just means testing and stating that the things were fixed in
meantime. Closing them would not solve anything.
Only problematic parts of the bugzilla are unmaintained areas (herds) of
the tree where the bugs have tendency to grow. The fix itself is not to
close those bugs, but motivate some guys to work on that area and became
developers so that bug number effectively became manageable.