I'm reminded of the 'Return of Mansell' in 1994 to do four races, at the behest of Renault.
Two positives came out of this, he backed Damon Hill's crticisms of the car up, and he won/inherited a win in the AGP ensuring Williams of the Constructors Cup.
The negative side proved the old adage ...... "You can't go home again", underlined by Mansell's wretched performance in '95 with MacDonalds.
Schikelgrueber age 40 will be very different to Schikelgrueber at 30, and my considered opinion is 'common sense' will prevail.
He'll keep the car at the pointy end of the field and bring it home in a decent position, podiums are probable and a win possible provided all the cards fall his way.
He can't win the drivers title, but he can score points for Ferrari, which is why he gets the drive.
If he is as smart as I think he is (
and I'm not and never have been a fan after 1994!) there will be no teaching the 'upstarts' a lesson, unless that lesson is in self control.