Speaking from a programmer perspective again, multicore support is a big achievement for the civ programmers. It'll unavoidably slow down systems with fewer cores, but it has the potential for huge speed improvement on higher end systems. This is a technological achievement. Single threaded programming is easy. Multithreaded is tough. Your PC is too slow? Welcome to PC gaming. Enjoy your stay.
It's also ballsy move. Big risk taking on the part of the developers. So was the Steam Workshop switch. This is the sort of life you want to see if you like the game. It means you have a team of guys actively working the code. They just should have made it an option, like other performance options (Also hard!).
It also sets them (and the niche) up for the future, being able to use advanced technologies to do something remarkable for PC gamers, as oppose to the static consoles or trying to adhere to legacy code and ways of doing things.