I've had a response from Slideshare/LinkedIn support for this issue - spotted the thread when looking for alternate solutions.
Thank you for your email and I am sorry for any inconvenience this may
have caused. We're always looking for ways to improve the SlideShare
experience for our members. This sometimes means removing features
that aren’t heavily used to invest in others that offer greater value.
Please know we continuously evaluate how features and products are
used, and make adjustments accordingly to focus our resources on
providing the most value to our members.
As a result, we have removed the ability to re-upload documents to
SlideShare. As a workaround, you can upload a new file to SlideShare
and delete the current one. Please be aware that this means we will
not be able to transfer any views/likes/URL's to the new presentation.
Again, I apologize for the inconvenience and we greatly appreciate
your feedback. We have documented the issue in order to track
additional reports of the problem and for consideration to be
addressed in a future release. If there's anything else I can help you
with, please don't hesitate to let me know.
Or put in other terms, "we don't give a damn". I can understand changes being made, but this seems arbitrary and no notice has been given.
I'd just uploaded a draft presentation for a talk I'm giving later in the week, so I can get some printing done and have the right URL ... except now that URL is incorrect and of course because the printing has already been completed, I'm going to have to pay for the whole print run again.