Don't you think it'd be too early for Shin to become a Great General in this same invasion campaign he achieved General status in?
No, because the Zhao campaign will last for years. I doubt Zhao will fall in less than two years, maybe more like 4-5. So Shin won’t have achieved Great General for like 7 years after he initially reached General. And Shin has spent 100% of the two years since he was named a General on the battlefield, and will likely spent 100% of the next few years on the battlefield as well. That is 6-7 years of day-and-night battlefield experience.
And if Shin pulls off the best or second-best achievements in a campaign that ends up destroying a major state, something that the OG Q6 failed to do, then he 110% has earned the same rank that they have.
So yes Shin will 100% be declared a GG after Zhao, no question.
Shin will need to display something more than just defeating another General in a head-to-head fight to be worthy of becoming GG.
Correct, else they would’ve just given him GG after he slayed Houken.
Shin needs to prove that he can lead his men to victory against other Great Generals, which is ultimately what I think he will do in Zhao. Whether that means against Shibashou or against Riboku (xdoubt), Shin is going to somehow prove that he can lead men to victory against a GG level threat, even though I still doubt that Shibashou will actually die in Zhao. To your point here:
All the Great Generals are more than just martial might. They're all capable of leading a campaign and defeating their opponents with mastermind tactics. It's tactics first and martial might second.
This is very wrong, even by the standards of just Qin itself.
Look at the Qin’s Golden boy in Moubu right now. Moubu is far from stupid, but Moubu is certainly not known for his strategy and tactics lol. Moubu almost solely elevated himself to Great General through use of his personal strength and martial might. Moubu is Qin’s number one commander right now, and tactics definitely play second-fiddle in the Moubu army.
Looking at other states, we have characters like Houken who was promoted from foot-soldier straight to Great General based literally only on his abilities as a warrior by Riboku himself,
We have Kanmei who didn’t bother with strategy or tactics at all, that responsibility fell to Jin Ou while Kanmei solely relied on martial strength to win his battles,
We have Gaimou who probably knows nothing of strategy or tactics and leaves them to Jun Sou while Gaimou only fights martially
And there are more examples but these are the most extreme.
The higher-ups in Qin don’t really care how much strategic or tactical knowledge you have, they care if you can lead your armies to victory through whatever means you see fit, and Shin has proven time and time again that with Ten carrying the strategic and tactical load, he can lead his men to victory without having to worry so much about those things and only using his instincts reactionarily. And besides, I won’t go into detail on Eikyuu but Shin showed bigboi intellectual growth at Eikyuu.
Overall, as long as Shin is leading his men to victory, Kanyou doesn’t care if Shin is shouldering the intellectual burden of his army or if Karyo Ten is.