Not really. The differences between Sanders and the "moderate group" of the candidates are fundamentally pretty negligible when you're talking about domestic policy goals.
The biggest policy issue is health care. The difference between "Medicare for All" and "Medicare for All Who Want It" is about violence of approach. The former seeks to abolish all insurance within four years - the later provides for a natural transition between two systems.
Democrats want more robust financial regulation and and a more progressive income tax. Bernie just wants MORE of those same things.
Bernie, and his very online army, don't care AT ALL how someone who isn't already among the converted will receive their message. They are blunt, uncompromising, and armed with the moral certitude that anyone who disagrees with them isn't just wrong, but immoral. They are blind to their candidate's obvious liabilities and they manage to piss off even committed liberals with regularity.
It would be a DEBACLE for the party if Bernie gets the nom. He might single-handedly swing the Senate race McSally's way in my home state. It would be BAD.
Socialism historically has meant that a central government controls the means of production (i.e., most sectors of the economy). If you look at Bernie's proposed Green New Deal, he wants to nationalize the energy and transportation industries, not just healthcare. He wants loose immigration and other progressive social programs that have zero chance of getting through Congress regardless of which party holds the majority.