Since last Friday, Bugzilla has a guided bug entry form. Together with documentation at https://www.mediawiki.org/wiki/How_to_report_a_bug (which needs an update now) this should make it easier for users to create better bug reports.
You can link to and access the guided form by attaching ?format=guided to the enter_bug.cgi URL, like e.g.
https://bugzilla.wikimedia.org/enter_bug.cgi?product=Wikimedia&component...
If you don't pass product/component parameters in the URL & link to https://bugzilla.wikimedia.org/enter_bug.cgi?format=guided the first page (where a bug reporter has to choose a product) still looks the same as usual.
I would like to thank the WMF design team and community liaisons for reviews and early feedback.
Happy bug reporting, andre