With that in mind, let's see which principalities should be on the map in my opinion:
Republic of Novgorod, capital:
Novgorod (we cheat a bit here with the Republic)
Principality of Pskov, capital:
Pskov (was a smaller lordship, allied with Novgorod for most of the time)
Principality of Polotsk, capital:
Polotsk
Principality of Smolensk, capital:
Smolensk
Principality of Turov, capital:
Turov (replaces Mensk, which also grants more safety for the Lithuanians at the beginning)
Principality of Chernigov, capital:
Chernigov (replaces Bryansk)
Principality of Volhynia, capital:
Volodymyr-Volynskyi (replaces Zhytomyr)
Grand Principality of Kiev, capital
Kiev
Principality of Pereyaslavl, capital
Pereyaslavl
Principality of Rostov-Suzdal, capital:
Rostov (replaces Yaroslavl)
Principality of Murom-Ryazan, capital:
Ryazan
(Principality of Halych, capital:
Halych - already discussed in Part 7)