RGIII is appearing to be a bust - not because of his physical abilities - because he has failed to be able to work through his progressions.
His rookie season was a success for several reasons: The Redskins scheduled opponents in season one was weak. He was more difficult to game plan for because the opponents had a healthier player with wheels that they had not seen much of at that point in time. He was healthier therefore faster. He was able to mask his problems more with his running ability.
Now over the years he has failed to be able to see the field properly and his decision making has been consistently problematic over the past two seasons.
Now the coach does not want him but the owner does.
The Redskins mortgaged their future for a player that seems to be a bust.