I am a big believer in Co-pilots being treated as u/t Captains and not as u/t pilots but this can be done when they are in the right hand seat.
There is a proven safe track record on the Herc with Captains in LHS and Co-pilots in RHS. The only control in question is the NWS if the Co-pilot flies LHS. During normal operation there isn't a problem. Get it slightly wrong during x-winds, and more importantly, assymetric especially during an abort, and it can all go wrong fairly quickly.
We may not lose an aircraft but may easily leave the runway and damage one. At the subsequent inquiry along comes the Captain saying that had he been in the LHS he may have prevented the accident but in the RHS was unable to do so. He is the Captain and still responsible!