From all the major flaws presented in Bitcoin one could say PoW is the major flaw of them all making the coin more centralized than even most people can't afford to keep up with other miners, these are day traders doing there thing again making profits on your losses, beware most say it's like gold it doesn't need to be fast but in reality it just isn't so secure.
PoW may have weaknesses but it's not bad. yes maybe you're right this system has injustice. Miners with small funds will lose to those who have unlimited money. but after that there are many ways to make a profit. bitcoin is not gold, but more valuable than that.