I think raising the minimum wage has good and bad sides to it. In the long run, it doesn't make an meaningful difference as prices will eventually rise in response. In the short term it would help a lot of people who already work in low-earning positions (myself included), but I expect it would be a short-lived windfall. It is very likely to increase the unemployment. Companies will expect more from workers who make a decent wage than from those who don't. Also moving from very low wages to a so-called "livable" wage also would mean that a lot of people would likely lose government assistance like low-income housing, food stamps, tax "refunds," and many other welfare type benefits. So I think if people start looking into how it might specifically affect their circumstances, it might not make much of a difference. (An example for where I live is that making 9 or 10 bucks an hour would qualify you for at least a couple hundred dollars of food-assistance per month, but not if your wages were 15.) This is just one "benefit" and many other have similar wage level cutoffs so I wouldn't expect an increase like this to really help many people in terms of their actual material standard of living. Yes, they would no longer be semi-dependent on the government, which is a positive thing, but either way the costs are simply being transferred from the tax payer (ie to pay for government assistance programs) to the consumer. People with the new wage would have higher taxes and less government assistance, not to mention likely a harder time finding a job, so overall I am far from convinced that it would help that many people substantially.
I would also add that McDonald's is a poor and VERY unrepresentative example. Don't forget that the minimum wage laws affect all employers, not just massive multi-national companies like McDonalds, where arguments can be made that profits would be minimally impacted. There are many more companies and industries where the increased wages would be catastrophic for them. A company with 50 employees getting a few dollars more an hour could easily see their wage costs increase by a half-million dollars per year. That is a big problem.