Off the top of my head the big draw is that science and war now interacts much better. Science and war were terrible with each other using the old system. If you grew, then your science was diluted and you would need to pump to catch back up and take away from your time playing. If you got chained then you most likely also ate a bunch of learns which means you not only have to take time to regrow, but you needed to repump the sciences you lost.

Tldr: not needing to pump science makes utopia better