They are hedging their bets because they themselves do not know how the customer will react to uninspiring machines posing as GP bikes.
They wont be posing as GP bikes, they will be GP bikes. They wont be total prototypes but that isn't necessarily significant, there was no requirement to be totally prototype until 2002. As far as uninspiring goes I think one of the major problems with motogp currently is that not many people are inspired by technical developments that they cannot see, which make the bikes less spectacular to watch. Bike racing is fairly conservative but encouraging independant chassis manufacturers is a step in the right direction and potentially more inspiring that we have currently.