I don't think that's right.
The season coefficient basically judges teams based on the number of games they play and Italy have benefited by being "more poor" than expected i.e: AC Milan fall out of the CL in 3rd place... they get bonus games in the Europa League. Roma finish 2nd in their group behind Slavia Prague by being poor... they get bonus games in the Europa League. It's a benefit to a nation having teams which are not good enough to really challenge but also good enough to beat lower nation sides and therefore having a lot of games.
Italy had 8 teams in Europe this season, England had 8 teams in Europe this season, Germany had 7 teams in Europe this season. Italy had 2 sides top a group (Atalanta, Fiorentina), England had 6 (Arsenal, Man City, West Ham, Brighton, Liverpool, Villa) and Germany had 3 (Bayern, Dortmund, Leverkusen). But, more crucially, Italy had a side finish 3rd in their CL group whereas England had 0 (2 came 4th; Man Utd and Newcastle) and Germany had 0 (all 3 sides qualified from their groups)...
...but then Italy also had 3 runners-up in the European finals last season (Inter lost to Man City in the CL, Roma lost to Sevilla in the EL and Fiorentina lost to West Ham in the ECL).
Perfect storm to get a strong coefficient, I'd guess, but not really a judge on how strong a league is.