It is a thought worthy of discussion. I had a CD ROM game that let you select what aspect of each branch you researched next, so you could focus on speed, armor, weapon, AA, or range depending on the unit type. So for instance you might leave your tank at level 1 armor, but pump the gun up to a level 10, or you might research the armor and gun to 5 but leave speed at level 1. Obviously as you progressed through time you would end up with a super tank, or FTR or TAC with all values being 10.
Also as there was X amount you could afford for research, you could completely ignore some aspects such as Naval or Artillery and focus more on 1 or two branches.