I've always thought the notion of 'complex singles' is a bit misleading. Yes they are more complicated but really a CSP and retractable gear doesn't really constitute a major increase in complexity.
I had a lesson in the Arrow during my PPL (because the school had run out of standard PA28s) and since then I've flown the C185C amphib as well and a few other types with CSPs. There is nothing difficult about them and in fact the Arrow could quite easily be used for PPL training.