When I was a tester my gaming machine was ~7 years old, well past its prime and gathering clutter. The game ran perfectly and loaded quickly, despite everything yet to be streamlined. Performance was rarely a issue unless something was seriously broken. The only issue for me was ping, as there was no Australian test server.
ESFF is a lot more complex than NNK and thus is forced to remain neater by comparison. I get the impression NNK could get away with more spaghetti than ESFF ever could, and it showed. I had a LOT of dramas testing NNK with rendering and performance. Looks is an arbitrary and almost useless method for gauging performance specs, depending on the setup 2D art can be more system intensive than animated 3D geometry - it really does come down to how it was coded.