Simeone would love to coach Lazio. Wouldn't that be something. Of course it won't happen right away, as he's still studying for it, and I'm sure he'll be looking to gain some experience elsewhere first. But as with Mancini, it could happen while he's still a 'young' coach. Maybe in a season or two.
For now I guess we'll stick with Caso. He was coach of Lazio's youth team for a long time and guided them to the championship. Surely it can't just be him that's to blame for Lazio's poor performance. Eventhough he is making a mistake in adapting the available players to his tactics, rather then adapting the tactics to the available players. But a lot of coaches do that, especially those who've been coach a long time, ego comes into to it I guess. Eriksson stuck with 4-5-1, eventhough he didn't have the players for it anymore, Zoff had his 3-5-2, Zac his 3-4-3. The exception was Mancini, who had his experience as player fresh in memory, and had no objections to switching from 4-4-2 to 4-3-3 when necessary. We may dislike him now, but in his first season with Lazio he achieved great results and was hailed for his attacking style of play. Only when he started to care more about Inter than about Lazio did it go downhill. But even a coach like him isn't a guarantee for success, look at Inter this season to see that. So in then end it shouldn't really all come down on the coach, whoever it is, they can and should play an important part in the equation, but it's a joint effort and players have a equally big part in it.