No Oda Nobunaga?

It seems to me that Oda Nobunaga is primarily responsible for ending the endemic local warfare of the Sengoku period and setting Japan on a path of stable central government. But what if something happened to him early on where he never manages to begin his career? Does Imagawa Yoshimoto become Shogun? If so, would his reign be anything like the Tokugawa, or more decentralized like the Ashikaga?
 
Imagawa Yoshimoto is likely to become Shogun since he had no real competition in the area, and he was allied to the Takeda and Hojo at this time, which would've made him almost unstoppable as I doubt any other clans would want to take on them three. It could lead to a slow unification if the alliance sticks. He would have to reward them both heavily though as I doubt they'd be happy to play second fiddle.
There are still challenges for the Imagawa though. The Ikko-ikki will have to be dealt with, one way or another. There is also the Azai/Asakura alliance. Despite his modern portrayals, Azai Nagamasa was a great commander and held together an unofficial alliance to fight the Oda for over ten years. If something similar happens here, then maybe the Takeda will see weakness and make a move themselves.
The Mori to the west are also another big player. They too caused trouble for the Oda.
His reign as Shogun (if he manages to keep it) would most likely be similar to OTL Tokugawa rule. It will involve measures to punish enemies and reward allies as well as keeping order and keeping things the way they are for the people.
 
It depends what POD, you are using losing at Okehazama it gives Yoshimoto a chance to become Shogun or try to control it, but by 1560 he is dealing with the Miyoshi Clan at its hight and a steady but powerful Mori clan. There still the Iga Ikki and Ikko Ikki, what happens with the Takeda and Hojo. In theory, an Imagawa Shogun could be much different than the Tokugawa it would be founded on a position of strength and legitimacy unlike the Tokugawa for the latter and the Toyotomi for the former. I have my own take on this POD for a timeline, but I've admittedly taken some liberties.

Then again if Yoshimoto does become Shogun I would expect the Mori to continue dominating in the West, The Chosokabe securing Shikoku, maybe even the Shimazu uniting of all Kyushu. Eastward it is hard to say the Takeda could still become a regional power along with the Hojo, however, what happens between them and the Imagawa could go a different way, as it unsure how their triple alliance with each other and the Imagawa was going to play out if Yoshimoto is not dead. For Central Japan, you can expect more of stalemate as the Miyoshi slides into irrelevance and infighting, and the Ikko-Ikki remain strong.

Anything that could result in a mutual kill of both men could see the Takeda poised to control Central Japan, the Matsudaira/Tokugawa risk being isolated, as Nobunaga's young son Kimyomaru would require a reagent, and might not be able to support them in their independence.
 
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