Priority Boarding
It is an issue but it also depends on Italians and routes. Try to enforce this on a packed FCO-SUF on a hot day in August. No way!
However I have appreciated when AZ staff made it. It happened at Heathrow and I was speechless. :-o

Lounges
I found "Le Navi" and "Borromini" in Fiumicino and "Manzoni" in Linate not that bad (if compared to Air France or KLM).
"Bernini" lounge in Fiumicino is horrible, I hope AZ will refurbish it now that AF and KL arrive at gates B.
I agree the SkyTeam louge at LHR is impressive.

Upgrades
Alitalia (CAI) gave me an update this year, on the FCO-LHR route. Ticket was an award one. I am neither CFA nor FTL, just E+ (Plat) with FB.