That will be great.
Not because I strongly wish Lazio to play serie B. I don't care at all about them. But one of the main problems Italians are facing is that in the eyes of the neutrals and the majority of football fans, the Italian football is filled with match fixing. That alone is pushing the viewers away. I mean, why watch a fixed league?
The English take proud in their fight till the last second no matter if they need the points or not. But in Italy, if both teams need a draw, it ends 0:0 or 1:1. If one team needs the pts while the other one doesn't, even if the team that doesn't need the pts is far too superior player-wise, the inferior team that needs the pts will win without any problems.
If a team is punished for that and ends up in serie B, the others will think twice before doing something similar.
In long term it will be useful Lazio to be relegated, even if in short term it might hurt Italy and its reputation (which is too low anyway).