You need to settle a 2nd city. Communism eliminates distance maintenance; it does not do anything to maintenance based on #cities (which is eventually capped, but IIRC is the larger component of maintenance if your 2nd/3rd cities are close to the capitol).
The reason I didn't rate it higher is what noto pointed out; workshops are basically forests unless you're in caste, which means you'd need, at minimum, CoL and MC before you'd be able to build a single improvement which the civic is truly benefitting. At machinery you have a GREAT improvement, but we're talking about a majority of the BCs where the only benefit is no distance maintenance. I don't see that beating +1

on every farm, even with a

cap. Drama or monarchy are both easier to reach than the MC ---> machinery + CoL route, and the benefit from a bio farm is better even still until guilds at minimum.
It's still a great early tech, especially if you build kremlin, but I'm not sure it beats bio or even democracy (which can troll the rest of the world with emancipation

and make cottages a seriously good deal all over the place).
One thing going in communism's favor is spy abuse though. If you take that or even democracy there is some strong incentive to spam out espionage because you're going to have a considerable lead over everyone in it for a long time.