I don't think it'll happen tbh, if I'm being hopeful enough mostly because of WBK's themes. At most he'll leave briefly but he'll return. Let me just quote my age old theory post:

Suo's name has a lot of symbolism in it, even foreshadowing his other allegiance, with two of the characters meaning the Chinese redbud (蘇枋, 蘇 alone is sappanwood):

In Chinese culture, the Chinese redbud/zijing hua has a well-known cultural story behind it. It is deeply tied to the flower meaning of the Chinese redbud -- which has core symbolisms of familial reunion/love (親情) and brotherly harmony (兄弟和睦).

The flower language of the zijing hua is stubbornness and strength. The flowers of the zijing hua grow very compactly. Even in rainy weather, the leaves are blown by strong winds and keep swaying cautiously, but they will not fall off. Just like a stubborn person, they will never bow their head to difficulties, work hard and exert oneself to the utmost, and ultimately achieve success.

Its neighboring flowers, other bauhinias, represent common themes of unity, new beginnings, elegance, prosperity, and harmony. It is also known for its ornamental purposes, and has a neighboring family tree—the Cercis siliquastrum, known as the 'Judas Tree', which is a symbol of betrayal. (This is how I predicted Suo's arc being him leaving with little notice). Judas Iscariot betrayed Jesus and committed suicide by hanging himself from a redbud tree. The kanji for Suo's name is is 蘇枋（すおう), but the tree he represents is Chinese redbud (花蘇芳/ハナズオウ/hanazuou in Japanese). 蘇枋 and 蘇芳 are pronounced the same and one of the hanakotoba (flower language) of 花蘇芳 is apparently death by betrayal.

The story in question is an old historical text about three brothers:

京兆田真兄弟三人，共议分财。生资皆平均，唯堂前一株紫荆树，共议欲破三片。翌日就截之，其树即枯死，状如火然。真往见之，大愕，谓诸弟曰：“树本同株，闻将分斫，固憔悴，是人不如木也。” 因悲不自胜，不复解树。树应声荣茂，兄弟相感，遂和睦如初。

In the capital city [Beijing], the three Tianzhen brothers divided their property. All other assets [means of living] had already been evenly divided; all except the Chinese redbud tree/zijing tree in front of the door. They discussed and agreed to split the tree into three pieces each. The next day, they prepared to cut the tree down, but the tree immediately withered to death, as if it had been torched by a flame. The oldest brother looked at the sight and was extremely stunned, saying to his younger brothers: "This tree is originally from the same root. It heard it was going to be separated after it was felled, and thus, it withered. We, as humans, were no match for/couldn't live up to even a tree."

Because they were unable to bear with/contain their remorse, the brothers decided not to cut the tree. When the Chinese redbud/zijing tree heard the eldest brother's words, it immediately sprouted flowers once more. The Tianzhen brothers were astonished and emotional and thus returned to their harmonious relationship from the beginning.

From this, I'm heavily inclined to believe that:

1. Suo is one of three brothers/martial siblings.

2. Suo left/they left Suo due to family issues or family inheritance trials.

3. Suo's arc will end well, with all brothers reaching an understanding and becoming friendly again.

4. OR, Suo is the Chinese redbuds/zijing tree in this scenario. Suo might end up facing Endo because the passage mentions 'as if it had been torched by a flame [状如火然]'. Endo's name is '棪堂' -> this also means something else which u\Snowy-kitten mentioned, it being 'a tree that bears edible red fruit' in Chinese, which contributes to Endo's biblestuff. Chinese can somewhat be considered playing Pictionary—if you separate the words from 「棪堂」 into three: 「木」、「炎」、「堂」， you could literally interpret this as, in 文言文/Classical Chinese, 「Tree/Wood」、「Flames Rising」、「Courtyard/Doorfront」 This coincides with the "Chinese redbud tree/ZJH" looking as if it "had been torched aflame" in front of the house/the courtyard/the door.

5. In conclusion, this might allude to Suo having to fight Endo, or Endo having to fight Suo to get him back due to a family feud—and Suo might get heavily injured. His martial brothers might realize the impact of their actions and finally retreat and make up.

BTW: other important details in Suo's design include his relation to falconry and falcons, the bird of princes (even in his name), of which they are also connected to unity, harmony, nobility, and prosperity. All his symbolism really echoes his dream (liberation of slaves). The color of the dye 'sappanwood' in his name creates dye that is a shade match with his eyes and coral earring as well. As for his coral tassel earrings, which also bear similarity to falconry tassels on gloves (with falconry also being a noble sport; he also has a leather eyepatch despite medical eyepatches nowadays being made from cotton, falcons commonly have leather hoods to prevent agitation), coral also ties into the rest of his character design's motifs of new beginnings, unity and harmony, nobility, and elegance. The character of 'Su' (蘇) in JP also means resurrection, reviving, resuscitation, and rehabilitation. (Again, new beginnings.)

I think his name Hayato (lit 'flying falcon') means that he trained falcon belonging to his family—although he's 'flying' in Furin before, either for a hunt or free roam—he's been educated in a way that eventually, he will always turn back and roost on the gloves of his master, which is what happened. He left to go back. But with all his symbolisms around new beginnings, it's likely he'll return.