Unless he dies after the 17th of December, Delhi is spared. The "pretender" Ottomans are not supplanted even temporarily by either Timur or a neo-Seljuk client state. Bayezid will sucessfully finish the Siege of Constantinople, which was going on when Timur invaded the Ottomans.

Aleppo and Damascus probably keep a lot of their people too. Smyrna stays with the Hospitallers, probably just to fall to the Ottomans. Kingdoms of Armenia and Georgia also have a lot more people. Samarkand will be decidely less great a capital if Delhi stands. This in turn could weaken the prestige and power of future Timurid rulers. Europe probably suffers from this. Several nations, such as Castile and France, seem to have traded with the Timurids. As well, an even stronger Ottoman Empire is VERY bad for the east. If Bayezid is present in presumabely alt-Istanbul, he will ensure an orderly succession. This means no chaos where Europe can rebuild. Bosnia at least, is in chaos. The Pope will probably want a crusade, and there will be another Nicopolis or Varna. Anyone south of the Danube is screwed. The usual capacity of nations for conquest is greatly extended by brilliant leaders. I could see Albania being completely absorbed earlier, as Skanderbeg won't even be born yet. Bosnia is lost too, and Croatia will be wide open then. A naval invasion of Italy is POSSIBLE, but I don't think it would work. Venetian lagoon is still too strong. Hungary is going to lose a lot of land.
Overall, this just makes the Ottomans a whole lot stronger, and perhaps Ming or Muscovy (in the future) can project power into a possibly vacant Central Asia. I would actually expect Timur's successors to move south and basically become Persia, because without the plunder of Delhi, parts of India and Iran are looking more attractive. Hungary and neighbors are going to get crushed if not destroyed early, and whether they turn west or east, I would believe Ottoman Kiev or Vienna.
