Well, it's a matter of feats. Ousen currently holds the better tactic feats than SHK does. You can argue that we haven't seen SHK in battle much, making it hard to judge how great he is in comparison which is fair, but I'm leaning towards Ousen for now.
Okay, I see what you mean. That's a good point. Is your overarching point that SHK is simply better at chief-related stuff than Ousen is, making him the better person for the job?
Right that's my overarching point. Ousen can be better in strategies, sure, but doesn't equate to him being the better CoM, when the primary job of the CoM isn't strategies, it's making the nation's military the strongest it can be. (Refer back to why Karin was selected as CoM for Chu). Strategists can do that better than anyone, however, that doesn't mean all strategists are of the same capability when it comes to that.
Look at the sheer foresight and eye of talent SHK had, he for years was looking at his goal, and for which he knew he'd need youngins who can rise up to be top tiers. So what did he do?
-> Raised Mouten as the top strategist of his generation
-> Raised Mouki as the top 3 strategist for his generation
-> The moment he saw Ten and from knowing about Ten's events he says "I've attained a good piece", proceeds to raise her to be top 2 strategist of her generation
-> Tried to recruit Kyoukai and Shin due to the potential he saw in them, while nobody else even made an attempt. Despite them not messing with him, he did everything he could from the sideline to stimulate their growth, even allowing them to stay together as a unit.
-> Groomed up Ouhon as well
-> Purposely held back the promotions for the M3 so they could further develop their skills. Purposely developed the M3 as independent units so they can enhance their quick-decision making on the battlefield (the thing you're saying SHK is inferior to Ousen in).
While bringing up ALL youngins that'll be the main stairs of the next generation. He also sees talents in utilizing his present generals properly and setting them up for the eventual unification. Ousen goes from Vice-General under Mougou, to being given the most important role in the Coalition next to Moubu (as the Shield to Moubu's Sword). Aware of Kanki's talents and personality, puts him alongside two veterans who could keep Kanki in check, while Kanki being able to carry them from a talent perspective. Hell recognizing Ousen would be the best out of YTW & Kanki in making on-site decisions of the campaign, despite Ousen never having led a single large campaign before. Like lordy, you can go on about this dude's vision.
Cause at end of the day strategies from the CoM are only ever gonna be good for initial starts of the campaign, no matter who the CoM is. Everything after that is all dependent on the generals there. See the situation with Juuki & Karin, she can't make strategies for Juuko without actually being on the battlefield. Hence, SHK couldn't make strategies against Riboku after Riboku countered his initial one, without actually being there on the site. But all of that stuff above comes before making strategies for grand campaigns or some shit.
Now as for who's superior out of the two strategically? I think they're both on par, and that's Hara's viewpoint as well, especially when taking into account historical events. Their stats progression reflects that as well. And in the series nothing has pointed to SHK > Ousen or Ousen > SHK in any definite manner for me to go with either. So going with SHK ~ Ousen. Example, if Riboku is able to edge out Ousen in their Shukai plains battle, then SHK & Ousen would be a dead stalemate.
