Is communism inherently flawed?
Yes, it doesn't properly take human nature into account.
Look at Russia, look at North Korea, look at Cuba. Hmm...
Inherently unrealistic yes, flawed... depends on what type of Communism you're reffering to. It works in Communions, and has worked in Catilona, Spain and Ukraine. But both those examples only lasted a couple years so it's hard to tell.