Fair enough, but not an excuse to the dozens of Polish AltHist writers who could do that but instead write ,,what if Poland Had Nukes and Lazers in WW2" jerk-off fuel (either Ironic or, dear god, Unironic)
And seriously , it's not all that complex - it follows the usual ,,if X won then system Y would be implemented" : if the Localists won then Poland is lost, perhaps this time forever.
If Mieszko Stary won then it would probably be a loose confederation of statelets that would collapse after his death or get invaded by the Germans. Władysław II would probably centralize his power and essentialy rebirth the country 1.5 centuries early - HOWEVER the main issue is the lack of the Second Piasts (Władysław Łokietek and Kazimierz the Great) who essentialy turned Poland from a third rate country into a Major local power and set the scene for the Polish Lithuanian Union, alongside the (untilatly fruitless) plans to create a sort-of Royal Federation with the Hungarians and Czechs by marrying into their royal families (unfortunatly the Pope sent them all on crusades against ottomans and they all died, so fuck you Vatican for that) - but in General a shift from Petty wars against Brandenburgia or the Paegans or local conflicts over Silesia, and into Eastern Politics - leaving Silesia in Czech (later Austrian) hands and sealing the fate of Outer Pomorania, but also bringing in a challange to the Muscovites, filling in the vacum left when the Post-Mongol states began collapsing.
Without all that it could leave a Far Weaker / Nonexistent Polish-Lithuanian commonwealth, and that already has large implications for the Future...