Came back from the U.S. into Rome yesterday. It was later on a Sunday evening and crowding was medium, I'd say. I was very concerned about it because I was bringing my 92-year-old mother with me. Turns out this is an excellent thing to do, because the wheelchair service nonchalantly skips ALL the lines. He marched us right up to a manned immigration booth and put us at the front of the line, in front of a young couple with a very small baby strapped to the dad's chest. I felt guilty but we went through - one U.S. citizen, one Canadian citizen/Italian resident - in nothing flat.
So I realize most of you will not be dragging your mothers around for this expediting purpose ;). What I wanted to say is that now the signage is exceptionally clear as to where Schengen-eligible visitors, i.e., those who do not need separate tourist visas, are to line up (Americans, Canadians, Australians, British etc.) vs. where European citizens AND RESIDENTS need to go. The EU line specifically said EU Citizens and Residents. It was not so clear at the beginning, and created much havoc for those of us who have Schengen-eligible passports but also residency permits.
There were also lots of employees directing traffic. The people arriving seemed to filter quickly into the appropriate lines, without a lot of milling about and arguing. So I'd say the chaos is resolving. There will be always be some chaos just to spice things up, but it's much better than it was a few months ago.
P.S. and unrelated to the topic: the wheelchair service guy also cleared people out of the wheelchair area at the baggage claim belt and skipped the line at the car rental kiosk. Then took us straight to the rental car. Great service after 24 hours on the road.