I think theWanderers suggestion is spot on. Not so much in that it would stop accidents occuring - if it all goes tits up in the last fifty feet for example, only the Captain or FO in the RHS is going to be able to even attempt to rectify. Accidents will always - unfortunately - happen regardless of the flight deck experience.
Why I think it's a great idea though, is that it removes the financial benefit to the company of having a PTF FO in the RHS...therefore starts to end this odious practice.
Not only that of course, but if something does happen to the Captain, the strain on the occupant of the RHS shouldn't be too big to bear.