As much as I love Vim and R, I think the experience is pointless without embedded graphs. It would be perfect if it was possible to view a graph in a Vim split.
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.
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.