The fact that I had to prefix that with "(presumably)"—i.e. I can't actually tell using my own expertise—is evidence of that.
Of course if the sophistication is more about what they needed to know in order to break the things (and make that code change), then talking about this subsystem by itself that's either way lower or roughly the same as what they'd need to know to build and operate their own centrifuges. Much less, if they only needed to focus on one part of the process (motor control) that would cause problems (which might just be a brief consultant call with our own nuclear physicists and engineers, I don't know, nuclear science details seem as mysterious to me as high level language details might to impoverished programmers), or about the same, if they knew everything the Iranians knew about the systems (did we ever find out if they got all the blueprints and so forth and built replicas for end-to-end testing?) plus a bit extra on how and where to make it break without easily being detected.
Anyway how sophisticated can they really be when they didn't even use source control? (Old joke... https://news.ycombinator.com/item?id=4052597)
> Sophistication has come to mean a few things, but its original definition was "to denature, or simplify". Today it is common as a measure of refinement
So no, it can in many cases even be the precise opposite of complexity.
It actually originally comes from "sophistry", which is an ancient greek discipline of wisdom and excellence. I would generally associate the word with a high level of complexity that has been expertly reduced and refined to an elegant quality.
But sophistry now means something rather different: using subtle, specious reasoning to deceive.