Porting this over to requests should be no problem. However, I don't think there is a replacement for the urlencode that is used on line 271. Is it ok to leave that urllib/urlencode usage?
@eflyjason pywikibot.comms.http is literally just requests wrapped into a pywikibot class with some modified features tailored to pywikibot needs. If the feature is supported by pywikibot.comms.http, then it is recommended to use primarily this. If not, then there is no other possibility than import requests and use that (or implement the missing feature into pywikibot.comms.http of course :) ).