Been thinking about the personal union thing between Hungary and Bohemia during the Jagiellon monarchs... wouldnt Hungary make a more natural senior member in that union, considering it is the centerpiece of all relations in the region, with a union with Croatia and vassalage of Transylvania.
Also, the main 'thing' in that era happened on the Hungarian border, the 'thing' being the fight against the Ottoman incursion, and Louis II died leading the Hungarian army, not the Bohemian one.