In my opinion cost of Tech and building are not as Important as seriously lowering the rate of population growth first.
I will start by decreasing the pop growth by at least five times and the have the rate increase some as pop grow insead of decreasing.
First of it is more realistic and will seriously slow down gameplay but still make litte difference at the start of the game.
You should mainly increase time to build stuff with perhaps 50 - 100% or so.
Yep I'd agree with that. Not sure about the build time though.