For non-novel readers, it is hard to not to compare between season 1 and season 2 casts. Especially for main roles. Even though Dylan Wan (season 2) performed well, I bet people will hard to move on from Arthur Chen (season 1) before accepting Dylan Wang. I myself need 20 episodes to familiarize Dylan as Ning Que.

I didn't feel any chemical romance between Ning Que and Sang Sang in season 2. Including romance involving Mo Shan Shan and Ye Hong Yu. Don't get me wrong, Dylan is a great actor. But he is in the shadow of Arthur. Life after Sang Sang, Dylan just get away from comparison with Arthur. I like Dylan's Ning Que as the protector of Tang. He is so Ning Que. But for romance matter, I still cannot move on from Arthur.

This is my opinion for the other new casts:

Ye Hong Yu: I like Meng Ziyi in season 1. She is beautiful. I like moment between her and Ning Que at the cave and lake. But in other hand, is too soft for a warrior. In season 2, Liu Yi Jun also fine actress.. She has a sharp gaze. Perfect for Ye Hong Yu as female warrior, but I didn't find any feeling between her and Ning Que.

Emperor of Tang, Li Zhongyi: I like both actors from season 1 (Lai Leon) and 2 (Bao Jian Feng). They are great in their ways. They are very lively. They surely give different characters as the Emperor, but I like those versions.

Empress of Tang, Xia Tian: I thought Kira Shi (season 1) is the perfect cast for this role. But after watch some episodes, I think Lian Lian (season 2) is also great cast.

Princess of Tang, Li Yu: Tong Yao (season 1) did well for portraying Princess as a devoted daughter and as a caring sister to her brother. Ni Yan (season 2) also did well portraying Princess as a leader of the empire when the Emperor is not available.

Archduke of Tang, Lei Peiyan: in the season 1, I feel Su Ke as very shifty and dangerous person. But at season 2, Zong Feng Yan didn't have much opportunity to develop the character because of the script. Actually, I wonder why Lei Peiyan still appears on season 2 because his royal status has been revoked in season 1.

Mou You (7th sister): I guess in season 2, the 7th sister didn't has significant role as the season 1 did. So I can't make further comment about Jade Lin's performance. I like 7th Rong Zi Xi in season 1.

Lu Chen Jia (Flower Maniac): Yi Lin Huang (season 1) is too soft as being a female warrior. But it understandable because the story mainly tell abut her relationship with Long Qing. Meanwhile in season 2, I think Wang Hui Zhen is fit enough to play as stronger Lu Chen Jia.

My favorite characters in season 2 are the Academy students (especially, 1st, 2nd, 3rd, and 12th), and Mo Shan Shan. Sorry Sang Sang, because of the story, you are out of the list.