Well, if not for Italy, Otto I would still need to reinforce his power trough a regeneration of the royal authority.
IOTL it meant intervening in an anarchic Italy, with a Kingdom of Italy rotting alive, with a papacy weakened and threatened, and raiders all over the place.
Would it be only trough sheer opportunism, Italy would have been the perfect target. But it also held a serious legitimizing power for an Otto who had to deal with rebellious nobles and the episcopal reorganisation.
A more problematic situation in Western Francia, critically if late Carolingians managed to keep Lotharingia? That could be another focus for Otto (admitting he's not butterflied away) but would eventually only delay things.
I'd tend to think that Otto dying between 952 and 957, Berengar still king of Italy, would be a good "as late as possible" PoD there. Liudolf of Swabia, still alive ITTL, would have a great legitimacy issue and couldn't focus on Italy for a time.
It would only delay things as well, there, and you'd have to cook something up to prevent Ottonians to establish a direct control over Italy, tough.
What may be probable, in an Italy-less Ottonian rule, would be less important Ottonian reforms on political and religious structures, a more important focus on Northern Europe (especially Western Francia) and a weakened Papacy.
It would imply, more or less short-term, either a strong kingdom of Italy (which may be hard to have), or another hegemon(s) in the peninsula (Provencal, Byzantine, Lombard, all of these,...?)