He is completely dishonest about presenting the Nordic countries as models.

Those systems are not just tax based, they also use government-controlled natural resources to hedge against the economic cycle: Oil and gas in Norway and Denmark, mining and timber in Sweden and Finland. This shields their social systems from recessions, which have a way of both decreasing tax revenue and increasing social spending at the same time, which in turn makes basing such a system on taxes only inherently unstable. If you want to know what can happen when you try to base extensive social welfare on taxes only, look no further than Greece, Spain or Italy.

He's openly misunderstood basic financial distinctions like secured loans vs unsecured ones. He regularly refers to Wall Street speculation and trading tax at banks like Goldman, when the Volcker rule has all but already eliminated proprietary trading at large banks (its happening at funds, which he doesn't seem to understand). He refers to Glass Steagall, then Goldman, and doesn't realize that Glass Steagall only applies to commercial banks. He calls the FTT a tax on wall street speculation, when in fact it will decrease liquidity in the market, cause asset prices to rise, and raise fees on funds thereby hurting and pushing out regular investors like you and I at a greater rate than actual institutional investors.

Also, his plan to make college free will actually hurt those he says it will help. The labor participation rates and underemployment rates for youths are already extremely high historically. Increasing the supply of degree holders while handicapping corporate profits (through higher corporate and small business taxes, higher minimum wages, etc) means more competition for less degree required jobs. Causing more people to flock to graduate school and scarce private schools to differentiate. Essentially making public college have the value of a HS degree and causing greater strain on youth employment.

This is why even left leaning economists like the well respected Paul Krugman, who is a democrat, are calling him out on his complete lack of understanding of how to run an economy.