I've voted "other" because I think personality plays a bigger factor in generalship (read: leadership) than talent, skill and aptitude.
At the top tier, everyone possess an abundance of talent, skill and aptitude - to the point comparisons of those really comes down to inches, not miles.
How those things are expressed is channeled through personality, and how effective that can be really comes down to circumstances more than anything. e.g. is Kan Ki better than Ou Sen and Yo Tan Wa because he engaged Ko Chou's 240K Army and won, or is that just a reflection of his personality? I'd say the latter.
I'd also say that experiences matter. Kyou Kai was the first of her peers to understand Ou Sen's Locust strategy on their way to Gyou. That wasn't because she was better than them, but probably because she was a more worldly traveler than them, so she would have a better appreciation of what an influx of refugees could mean.
To take it back to the question of Shin and where he peaks as a general - I don't think he lacks for talent or comes up short compared to anyone. I think the blue print is there, more or less, and that he'll certainly belong in that top tier. I just don't think it's really worthwhile trying to determine who he'll be "better than", and more worthwhile to discuss whole he'll be most "approximate to".
tldr; I think Shin peaks in the top tier, and outcomes of battles, clashes, etc. will come down more to personality and circumstance than anything else.