This is what kind of thread I was looking for!
For a prosperous Hunyadi /Korvin the POD must 1490, when Matthias died in OTL. Let's say he lives ten years more. This ten year is crucial for securing John Korvin's succession and Matthias's conquests at least in Bohemia.
In OTL Matthias was just about to make a deal with Maximilian, wich would give back to the Habsburgs the territories wich Matthias took for 700 000 florins and for the acceptance of the succession of John's. They would probably sign it after the death of Maximilian's father, Frederick III, since he opposed the deal.
If it all goes flawless, then we would see John Korvin emerging as king of Hungary and Bohemia(peripherial) by 1500, probably crowned earlier.
I think when John would succed, he probably wouldn't continue his father's active expansionist policy, but he would stenghten his positions within his realm. He would porbably maintain his father's policy towards the turks too, reducing the confrontation with the ottomans to minor border clashes, and keeping up the quality or even strenghtening the southern borderfortsystem.
His first real chance to expand his empire would be the first war of the league of Cambrai against Venice(1508-10) in, when he could take Dalmatia from the venetians. The second one could be the death of Vladislaus II of Bohemia(proper) in 1516, when he could take the remaining part of Bohemia which was still not his. Ofcourse, first he would have to defeat the local supporters of Vladislaus's son, Louis's, who at this point is still just a kid, and probably the polish too. If he would win, wich is more than just a simple probability, he could seize all of Bohemia and get back the 13 hungarian cities in Szepes wich were in polish pledge since the time Sigismund of Luxemburg.
What could happen after this? what do you think?
(BTW: Didn't I just wrote a concrete TL core here, did I?)
(BTWBTW: Uhh I just red what I wrote, lectors welcome.)