I think a good fix is if research took both far less time to complete and produced far less science. Like I said above, multipliers should be 50%, not 7 fold. second, it should take weeks, not years, to finish all the research. Of course, in that case, what benefit is there to leveling up kerbals? A good fix here is for kerbals to boost the science produced...perhaps, they boost the multiplier. A level 0 scientist can process science in the lab at 100%, a level 5 scientist can process in the lab for the full +50% multiplier.
Then again, as SorryDave has pointed out...perhaps the point of the sciencelab is not science, but money. The game maker presumes you will have unlocked the science tree, so producing effectively infinite science is merely a way to allow late game players to use the strategy of science to funds a time constrained but infinite supply of money to run their post-game sandbox.