You don't need pressure to write with a fountain pen -- at all. (The modern competitor is a rollerball, not a ballpoint; rollerballs don't give you amount of flexibility on nib grind or opportunities for flex and shading effects that you get with a fountain, but at least you're not forced to use tons of pressure). Allows different, more comfortable grips.
I'll second this - using a fountain pen is worth it just for the ergonomics alone. Before I used (not inexpensive) rollerballs, and even then my hand would be hurting after a test or exam, but with a fountain pen I could easily write for more than double the time. It also worked out cheaper too - a $10 bottle of ink with a $20 pen lasted me the duration of my 6 year course, and the bottle is only half-empty.