[Gregstrom]

Re: Specialisation.
I'm not sure tech levels decrease in cost in RL. Maybe in relative cost, but probably not in absolute terms. Did creating the steam engine cost more money than the jet engine? I suspect not. As a % of GDP, maybe steam cost more. One of the reason tech costs grow in games is to (partiually) balance out economic growth, so you have to keep allocating roughly the same percentage of your nation's resources to keep up a similar rate of research.

Re: Uncertainty. I quite liked the MOO/MOO2 uncertainty factor. You paid the list price and had a small chance of working out the tech, then the odds of discovery increased with further investment. It was better for SP than MP though, as the luck factor could really mess you up.