Hi Rainer, I have wondered about what you suggest as well, from the point of view of trying to modify the long pieces of R code which are embedded in strings in ob-R.el. I think this would be easier if they could be tangled from R code blocks in an org file. So from that point of view the idea has a +1 from me.
I am not so convinced that having all the elisp code in an org file would be convenient, since I am worried that would break the interactive features of elisp programming. (edebug, find-function, paredit, ...). But if you are doing the experiment, I would be glad to see what you come up with: the benefits might turn out to be worth the potential drawbacks. -- Aaron Ecay