If you want graphs, you're probably not working at the terminal anyway and you're most likely using gvim that integrates nicely with our desktop environment. You can display the R graphics next to the gvim window.

This sounds like an excellent use case for withoutboat's[1] (aka tatterdemalion[2]) notty[3] terminal protocol project.

[1] https://github.com/withoutboats [2] https://news.ycombinator.com/user?id=tatterdemalion [1] https://github.com/withoutboats/notty

Could Tektronix emulation somehow be used for this? Then you could, in theory, display graphs in a vim/tmux split

http://www.cmbi.ru.nl/~schaft/mxterm/pictures/tek.gif

I used TMux to do exactly that. It worked good BUT RStudio is so good.

The enemy of Vim with R is RStudio. It works so well for me I haven't fired up Vim with R in over 3 years. Also I find RStudio Vim to be good enough for me.