I tend to agree somewhat but I just changed my scientist to more useful villagers like builders, healers, farmers and most importantly, breeders. Once I was done with tech research, I just didn't bother having scientists and there have been no adverse effects to this so far.

The boulder is one of the last puzzles to solve. It does take the 'right' villager for it to be accomplished. I hopw that I did not let any 'cats out of the bag' on this reply...

Your villagers automatically stop researching once you have all the techs bought. I find it most useful to not check their boxes in later stages of the game, that way when you have everything bought they automatically start working on other things they are good at without your intervention instead of just standing in the middle of the village not working