Transfers from 2D to other terminals should become much easier once Aeroports de Paris gets its act together and does not require security screens in CDG for pax that have already been screened at other Schengen airports. Apparently something like that is in the works, but not sure which terminals are concerned first.

The current situation with having another security screen usually performed by people whose IQ, understanding that you're traveling and politeness is that of a rotten cucumber + the understaffing of passport booths at CDG can make transfering a hazardous endaveour.