No the force of the drive is a minor component and can easily be demonstrated. The mechanics related to the drive and the ability to convert that energy is what counts, not how hard you push. Have seen my DD easily step and throw 65mph in flip flops. Safe to say she was not pushing. The fastest she ever threw was 72mph and worked in the 67-68 range. She had very good leg drive and if you do the math she was about 6% better when going full out off the rubber. While 6% is nothing to dismiss there are much more important things to focus on than increasing leg drive like generating resistance. IME increasing leg drive is what you work on when you get everything else working properly. Have seen many a pitcher get caught up in increasing leg drive while having only 1 or 2 of the 4 points of resistance. That is pure folly. Until you have all 4 points of resistance and can actually transfer the force you create with the legs you are wasting your time be it with or without a gadget.
(now to find the 4 pts of resistance and make sure I understand correctly, Thank you.)