My understanding is that 3e and later editions aren't any more complex than previous, only that players are expected to learn the rules instead of being completely at the mercy of the DM.
It's not particularily clear to me that there's really all that much of a complexity gap period, let alone in expectations.
Putting my 2E handbook (excluding the pages of spell lists), my PF core rulebook (excluding the pages of spells/magic items/DMing stuff) and my 4E PHB1 (excluding the smaller list of magic tems/rituals)side by side... frankly they all come out to about the same.
