The simplest and easiest tech rules I’ve seen (This assumes a five power game (e.g. A&A 1942)):
At the start of the game, all powers but the Soviet Union roll one die against the tech chart. What ever result they land on is now theirs, even in the case of repeats. Jet Fighters for all four rollers is possible, if statistically unlikely.
Short, sweet, random, and the tech is used for the whole game. Why not the Soviets? “Should not have purged your scientists, Stalin!” Real reason: letting the Soviets roll would allow the Allies to have an extra tech over the Axis.
One could even use this in the bid process: I’ll take the underdog, but I get (two rolls | targeted roll | I get to pick my tech) for doing so.
-Midnight_Reaper
P.S. Minor text edit.