Math has implemented explicit functions to cache rendering in the database, which is not used in production. All new code uses BagOfStuff cache, which might also end up in the database, depending on the settings. Therefore, I don't see a reason to keep the math(oid|latexml) tables.
MathSearch uses the inputhash and the inputtex in some situations, but this can be replaced with onMathRenderingResultRetrieved which in the end reduces join conditions.