Attacking in Northern Mediterranean basin would be seen as a threat by the Senate, and would cause similar consequences than siege of Saguntum, except that this time not only Gallo-Greek cities would join but as well mediterranean federations (Elysces, Salyans, etc.) : Hannibal could kiss goodbye his Gaul mercenaries (celtic or not).
With, of course, the sill likely turmoil in a Carthagian Senate lead by Hanno II or another Africanist leader if Hanno is killed, already more or less romanizing IOTL.
I'd see more likely Hannibal building his own personnal kingdom in Spain, and ending being pressured by Romans, Carthage and Celtiberians at this point.