First, I should mention that this post is mostly going to focus on how this VN improves on the original content from Shin Koihime Musou. The reason is fairly simple... if you like the series, you'll eventually play this, and if you played the original Shin Koihime Musou, then that is probably what you want to know. I know I would.
Next, I will go ahead and come out with it... I loved what they did with this path. The degree of added detail in this VN is actually higher than in Souten no Haou (Gi/Wei), and at least part of this is that it adds in a huge portion of time in the prologue, added story in the later areas of the game, and significantly revamped scenes involving the much larger cast of characters available to the somewhat sparsely-populated (comparative to Shoku/Shu and Gi/Wei) of the original.
The prelude (the period of the game starting with Kazuto's arrival through the Yellow Turbans and Dong Zhuo eras) is so completely redone as to be unrecognizable. Son Bundai (Sun Jian) being both alive and present in this part of the game alters how it begins dramatically. Ienren (her manna) is like Sheren/Hakufu magnified with a foul mouth and a fighting power roughly equivalent to Ryoufu/Lu Bu. She is harsh with her enemies, domineering but thoughtful with her subordinates, and rules her people with an iron fist in a velvet glove. Under her tutelage, Kazuto actually ends up pushed into the bloody/dirty parts of war, and as a result, he ends up a bit fiercer/harsher than he is in the other paths at times.
This path does indeed follow the basic bones of history (if you know what happens with Sun Jian and Sun Ce in the Romance of the Three Kingdoms, you know what I'm talking about), which matches the original events of the path in the original Shin Koihime Musou. However, because of the experiences in the prelude with Ienren, the emotional moments were all the more poignant, and I felt myself able to empathize more with the characters as a whole than I did in the original path, where things seemed to move far too fast through that part of the game.
The generalized 'fattening up' of the story is present at all levels, and the story is much more complex in the particulars as a result. While this has the effect of making playing all the way through this path somewhat exhausting, I felt it was worth it in the end.
The extra heroines are something of a mixed bag. I really liked Taishiji and Raika, but I despised Pao and was disinterested in Teifu (yet another drunkard older woman in a game that already has way too many).
I do want to say that I really seriously don't understand why they kept the system where you can't read all the heroine events each chapter. Sengoku Koihime allows you to read all of them, and it didn't seem to hurt the story... and it was immensely annoying to end up seeing some of the scenes that were slightly out of line with the current progression of the story. Only the 'ruler' heroines' scenes perfectly matched what was going on in the story as a whole, and that disrupted my enjoyment of them immensely.
Last of all, as rumored, there is indeed an 'alternate' ending to Go's path, unlike Gi's. This ending branches off at the most dramatic/sad turning point of the original path and gives you a 'what if' for if
Shelen/Hakufu didn't die from the poisoned arrow.
This alters the events that proceed from there and the ending as a whole greatly. I honestly cried happy tears at this ending, and for those who are displeased with that particular turning point of the original path, it is a treat.
Seeing Meirin and Shelen holding their children with Kazuto made tears well up endlessly in my eyes...
Anyway, that is my commentary on this game, for those who are interested.