Attacking marginalism head on is not likely to succeed, and it hardly matters. To the degree that it is science it is still bound by the larger context of ‘macro’ effects of whole economies, and if it is pseudo-science it will nonetheless prevail over rational argument. The issue, and here marxism confounded facts and values in its brand of scientism, is the creation of a society according to the values seen in a challenge to its evils of ideology and class.
The methods of calculus are at best a side issue. Like fly casting the question is, what will hook a trout? Here what will hook an economist is an argument dressed up with calculus. If these methods have really produced a macroeconomic science, fine, but it is very doubtful if this is the case, but the arcana revolve around some very had to penetrate mysteries, such as the Arrow Debreu and advanced analysis. The experts are confused and the non-experts can’t enter the game at all: it is a class based esotericism. I think postcapitalism is being delayed by mathematical fixation, we should change the rules to robust models of a simpler and better founded variety. I find it doubtful that a form of communist economics is forever banished because of the theories now current.
The question of how to treat whole economic systems with models, mathematical or not, remains unsolved, so we are always back to square one as we note that mathematical algae bloom in theory now accompanies the final triumph of neoliberal domination. Is the mathematics simply a smokescreen?