Here is my armchair answer:
It's true that in SUSY theories one can often compute many (perhaps even all, in this situation) quantities of interest but these calculations often rest either up a well-defined path integral formulation (which then localizes (pdf) to a sum of finite dimensional integrals thanks to SUSY) or operator-based formulation (as in the superconformal minimal models).
I think that if you have a formulation for quantum field theory like Martin Hairer's that takes the path integral seriously and works for traditional simple theories like scalar ϕ4 theory, then what you would want to do is first construct the path integral measure of N = 4 SYM and *then* show it localizes to a finite dimensional calculation.
My guess is that this will be a lot harder than constructing ϕ4 theory unless you can leverage SUSY from the beginning, considering it has so many more fields and exists at a critical dimension for the RG.