It looks like Mazzarri knows Napoli very well like it was predicted, as he has history with Napoli. They have a talented squad with a lot of attacking potential. If the Napoli players can quickly adapt to Mazzarri's new system and play together as a unit, they could be a force in Europe. For this goal to achieve, The club owner and board should be ambitious with their plan and investment.
Current Napoli is different to Napoli were managed by Mazzarri before. Now Napoli is a holding Champion who has mentality to compete at the highest level. Mazzarri as an experienced manager who has a proven track records wont have big difficulties to guide Napoli with big project in the future.
That`s exactly the hope, that`s why they called Walter Mazzarri.
The Napoli management hopes that the team and players adapt quickly to Mazzarri`s game in order to contain the damage done by the previous coach. And seems works.