part 2...part 1 all the characters were too bratty and annoying, in part 2 Sakura is the only one that didnt grow up at all and is still just as annoying, but the other characters developed well and the music got way cooler.
I disagree, if anything Sakura is one of the only people who have changed after the timeskip.
1. She doesn't use that Inner Sakura thing to express her feelings.
2. She puts her faith in Naruto and cares more about him then she did in the original series.
3. She is more confident in her abilities.
4. She is not fangirling over Sasuke and not begging for his love like she used to.
5. And she has actually improved her abilities.
Her "hitting" Naruto in Shippuden is mostly filler anyway.
If your looking for characters who haven't developed those would be: Shino, Tenten, Rock Lee, Neji, Kiba, Ino, etc. They act more or less the same because Kishi doesn't feel the need to develop them.
For me I prefer Shippuden as well.