I strongly agree with this because:
- To have Ctrl-Y mapped to redo is standard, for example Sublime text has Ctrl-Y mapped to redo. Also Rstudio used to have Ctrl-Y mapped to Redo until recently.
- There is already an emacs mode in R-studio, so if you want emacs, then you could use that. The point of the "default" keybindings I think should be to be "standard", that is, to follow the rule of least surprise.
- To Yank when you want to Redo is super surprising! It not only pastes some text you certainly not wanted to see, it also breaks the the undo/redo chain so that you will never be able to redo what you wanted to redo.