I guess suggestions to bring back old options are not popular but I think I can make a good case for this one. Until a couple versions back (I think), one could easily publish an RMarkdown document to RPubs just by going on the Source window and clicking on "Publish Document": it was one of the two options (the other being "Publish to RStudio Connect"). Now it's gone. One can still publish to Rstudio, but s/he has to knit the .Rmd file first, and then the options appears in the "Publish" button of the preview window. This risks having many people miss it, and incorrectly assume that the "Publish to Rpubs" options has gone.
On one hand, I understand the interest in publicizing RStudio Connect, which is a commercial solution and offers much more than simply publishing static HTML documents such as RPubs does. Most of all, it offers a secure publishing solution to share various kinds of artifacts among members of the same organization. For this reason, Rpubs and RStudio Connect, IMO, don't compete: one is aimed at free, public sharing of HTML documents with the world, the other allows secure sharing of much more diverse content with people inside a certain team/organization/community.
On the other hand, one of the reasons of the success of RStudio is its free Desktop version, which is adopted by a vast user base. And RPubs allows many of these users to easily publish documents and to find a lot of knowledge shared by other users in various organizations around the world. I don't have usage statistics for Rpubs, but I think it's extremely popular among users both for publishing and for learning about R & Data Science, by reading other people's reports.
I suggest that you bring back the "Publish to Rpubs" option in the "Publish" menu of the Source window, at least for the free version of RStudio (RStudio Desktop).