delete.py with botpasswords seemed to be the only way to get around the OAuth issue with this script. I've been using this for some time until today where it broke. I cannot delete more than one page without pywikibot asking me for the password every time (pages to be deleted suplied with the -file:todelete.txt option).
>>> MediaWiki:AllmessagesnotsupportedDB <<<
Do you want to delete [[bs:MediaWiki:AllmessagesnotsupportedDB]]? ([y]es, [N]o, [a]ll, [q]uit): y
Logging in to wikibooks:bs as MarcoAurelio@bot
>>> MediaWiki:AllmessagesnotsupportedUI <<<
Do you want to delete [[bs:MediaWiki:AllmessagesnotsupportedUI]]? ([y]es, [N]o, [a]ll, [q]uit): y
Logging in to wikibooks:bs as MarcoAurelio@bot
ERROR: Login failed (Aborted).
Password for user MarcoAurelio@bot on wikibooks:bs (no characters will be shown):
##Degug##
{"login":{"result":"Aborted","reason":"Cannot log in when using MediaWiki\\Session\\BotPasswordSessionProvider sessions."}}