I think Thiago is playing in a more povot role in the spain system. At barca he plays a more attacking style and at spain he controls the game. People might notice that isco can be like Juan Mata who won the Golden Boot award at the last U21 Cup but Thiago can be like Xavi but with more flair.
So i guess people are used to scoring and tricks and that why many many people arent impressed by players like Busquets,Xavi,Iniesta,Alonso,Martinez,Schweinsteiger etc. I give all the credit to Thiago hes the leader and the brain he could easily score the same way as isco does if he would play in a more forward position.