Regarding the job queue, another item of note is that there's a
general perception on enwiki that the job queue is either unreliable or
too slow to the point of uselessness when it comes to updating the links
tables (e.g. categorylinks) when time-related parser functions are used
(e.g. using #if to test if the current date is past a threshold). So
people run bots to do forcelinkupdate purges.
There are also sometimes
complaints that links tables aren't being updated in a timely manner
after edits to templates, as in things aren't updated weeks later and people reply that the job queue is just really slow. Then usually someone does null edits on the pages transcluding the template.
I don't know if either of those issues are
related or otherwise in-scope, but I mention them Just In Case.
-- Brad Jorsch (Anomie) Software Engineer Wikimedia Foundation