The ability to provide TSQL (as used in the Data Explorer) and return the output could be very powerful.
A similar capability could be achieved in a different way using bigrquery / dbplyr and the stack exchange public dataset on GCP, but if there were a way to do it using stackr and the data explorer, it could be even simpler and more accessible (no GCP account nor authentication necessary)
I had a quick look around and it looks like this functionality doesn't (yet) exist (in R, nor in anything else).
Could be a very useful capability