Well, last career I played with 30% science rewards (not using MPL) and I found it not that challenging. Quite easy in fact.
I want something that would incentivize me to explore something more than Duna.
I entered this forum to see if there are people that played on 10% sci rewards and think that it is far too hard to try it because I currently assume that 20% is not that different from 30% but 10% would actually be next to impossible.