Especially stuff which gets worse in capitalistic systems (e.g. a widening social gap between rich and poor) and stuff nobody feels responsible for (e.g. some environmental problems) needs to be solved in some way.
That kind of stuff happens with crony capitalism. The big players get bailouts and the average people lose their homes. A truly free market would solve more social problems than it would create.
Yes, but I'm certain it is a problem in all forms of capitalism. Social capitalism is actually supposed to lessen those effects, however the politcians might call our system this name, but often they are actually doing the opposite - like with those bailouts.
Does your truly free market allow monopolies?
If someone comes up with a good or service that is better than anything else sure. If they try to inflate the price other people will come up with a cheaper version forcing the first group to drop prices or go out of business. Monopolies are problems when states interfere with markets.