I have a few wishes-
Naval Combat to fully add to the Republics and everyone else- (It was important!)
With ability to seize merchant fleets for your navy akin to what happened at Sluys.
Emperor titles are just ceremonial kingdoms-
The Byzantines and the Holy Romans had nice titles but on the practical level were equivalent to Kings.
Holdings to be reworked bit-
Ability to convert wrong-type holding for a fee-
Palaces- For King and Emperor ranking states of any type-
Special Castle Holding meant for a large magnate-
Costs a pretty penny but gives good advantages, made from an existing holding being converted. The HR Emperor doesn't get one unless he solidifies control of his realm tightly.
More flexibility for CBs and terms in war, Byzantines and Turks can go all out at times for land and ability to add/subtract terms. Ability to use your Kingdom Claim to take specific duchies akin to the Hundred Year's War.
De jure wars for more than a province, for entire parts of a kingdom.
Vassal structuring-
Ability to confine certain families to perfectly made duchies following lines, for a price.
Archdukes in the HRE for Kingdom titles in a 3.5 area of rank.
Byzantine Governors instead of dukes and feuding noble families.
Other wishes for better for Pagans/Mongols, Catholic Church, and Other things are for later.