Hara would fumble hard if the other states don't put up a decent fight.
If Raku'uKan is just another mid general than Tou won't get a chance to show off his true abilities
Gouhoumei has been built up for years and deserves a few arcs where he's a proper menace
Yan is the state they know the least about so there could be a few someones that surprises Qin
Imo things will be great.
1. Manga Chu is set up as a super gigantic challenge, a literal superstate and they will be even boosted by people like Renpa and SHK. They are and will be outrageously stacked. Lol.
2. Wei will clearly be a very hard challenge. Overall, below Zhao and Chu but that is totally fine. With prime Gohoumei leading it, it will be a battle between true top tiers. If Hara follows history, Qin Six Ouhon might be the main star from Qin's side. Shin will be involved too, I think. Multiple Qin Six, Wei is a powerful huge ass state.
3. Han will take less than some others, but Hara has already gone out of his way to hype Great General Raku'a Kan significantly. Definitely no cakewalk even if easier than some others.
4. I don't think Ordo is the best current Yan has to offer and Ordo isn't weak at all, he wouldn't beat a Great Heaven but he ain't a weak Great General. I think there might be some sleeping tiger there, perhaps some monstrous ex vassal of the God of War Gakuki.
5. Qi...I think Ousen being the final villain and leading it against Qin will happen. Nothing else to say. Lol.