I was pondering this before and thought, in all my time supporting Everton (I'm 31) has there ever been a manager signing to really get excited about?
Koeman was probably the most prestigious name but even he had something of a chequered managerial history. Martinez and Moyes had decent reputations but both were gambles for different reasons. Smith, Kendall (mk III), Royle and Walker before them - although to be honest, I probably wasn't old enough to really gauge reaction to a manager signing.
You are right. Most of the managers that have come into the club have done so under dire circumstances, apart from Martinez and Koeman. I would say that Martinez had the most stable environment after Moyes' relative success, as he had a decent squad who all knew their roles and a solid defence. Although the season we finished 4th was good results wise, Martinez first season was the best season to watch the blues in the PL. It was exciting football, with goals but also solidity learnt from Moyes. The fact that he couldn't retain that solidity was his ultimate downfall, but dare say it, I would rather have a Martinez-like coach at Everton any day of the week over Fat Sam.
However, it is what it is.