May be use R-core instead of R-base for building rpms. Should be (a bit) faster.
In my vision the most useful setting for R usage in openSUSE would include an opensuse.install.packages() that first tries to install from d:l:R:released (or a dedicated repo) and only, if not found, downloads from CRAN. May be even a check of available versions included.
The same should work for special versions of available.packages(), update/uninstall etc.
Installation could happen vis sudo or even play around with relocatable packages into ~/.R/lib for simple users.
Leap would ship R, rstudio, rkward, all packages would come from d:l:R:released. To be useful d:l:R:released must be populated and be kept up-to-date automatically. Not a small task, but may be a possible one.
If R-* packages are in Factory, they should be in Maintenance, too. But I never managed to get even R-base into Maintenance. And that would be really useful!
For installation of packages a format like tex-packages ""zypper in 'tex(multirow.sty)'" could be possible: zypper install 'R(jsonlite)'