I find the lightsaber forms amusing concepts, but as with all things I don't really believe a lightsaber form itself has much influence on he capability of the wielder, rather people gravitated to it depending on a personal preference on a philosophical state of mind. After all the Jedi follow the force first and formost, their capability behind the blade depends on both their physical and mental conditioning first and foremost and form third.
Sure, there are some advantages to each firm but it is important to stress that it is not as important as the person behind the blade. The forms are not discussed in movies in great detail because it isn't relivant, but rather that the personality dictated the form that they took. After all, yoda was formless because he exclusely use the force to move himself around, does one suggest differently in that he chose that form? Or simply what he was? Is a formless character inherently inferior to one that has adopted none but simply a force of will and blade?
My personal opinion is that most for,s are capable of doing most functions, with the exception of the duelling style which is naturally weak to blaster bolts. Hence like with all things martial related in the end it comes down to experience and a quick mind and body