Carthaginian victory at the Metarus has always intrigued me. I concurr with those who see Mago evacuating Spain and landing in Italy, most likely in Liguria or Etruria. In the true TL Mago had been given orders to land in northern Italy and try to link up with Hannibal. It only makes sense that he would do that now as Hannibal and Hasdrubal are both close by. Hannibal left Hanno in Bruttium with an army, so those suggesting 2-3 fronts are on target I think:1) Liguria/Etruria 2) Central/Eastern Italy (Hannibal does not make an attempt on Rome) 3) Lucania/Bruttium.
War weariness was absolutely setting in. In 209 12 Roman colonies opted out of the war. The fact that some Etruscan towns were still ready to revolt when Mago landed demonstrates that the loss of Capua and Tarentum were not fatal to Hannibal's strategy. Scipio is certainly recalled. A showdown between Scipio and Hannibal was inevitable, but Hannibal has the edge here because unlike Zama, he still has a large veteren cavalry force. It's more likely that Hannibal is able to nudge Scipio into fighting on his terms than otherwise. Scipio does have a solid army-honed by years of fighting in Spain, plus he brings the best of his Spanish allied troops to the table.
A defeat of Hannibal means simply a prolonged conflict with Rome still emerging victorious.
A Scipio defeat likely brings peace on terms more favorable to Carthage: Rome evacuates Spain south of the Ebro and the Carthaginians leave Italy.