raised cockpit = perturbed airflow for the lifting fan
if only the VMC had the bunk cockpit then the Price of all three versions would hve raised
Also, it's really expensive to make a stealthy bubble cockpit like for the 22 (look at the choice made for the T50).
http://en.wikipedia.org/wiki/Sukhoi_PAK_FA
So it is a matter of priceS and overall effectiveness.
The Crusader had poor rear view and was an awesome dogfighter during Nam.
The top scoring aircraft of all time (the 109) had an enclosed canopy too
