presstab has a solution for the cpu bottleneck
I think less blocks is fine - orphans also cause unnecessary strain
Yes lots of solutions can be done for CPU. That is the easy part. I am leaning towards 45 -50 sec target time, and stake starting age of 1 day right now. It is not purely my decision.
What effect would be created by increasing the minimum required coins to stake?
Changing the minimum coin age would put more coins out there available for stake. This would increase the net stake weight, which would increase the PoS difficulty, which would lower the Annual Stake Percentage, which would help keep inflation from running away. At least that's my theory.