There’s been a lot of progress/improvement in KCD since release. That said, it’s not yet perfect. What would it take to get there?
It seems some are still experiencing an occasional gamebreaking bug. Those bugs obviously need to be fixed. Beyond that, there’s not a whole lot. So what’s left? (To me, the ashes/hardcore DLC have potential move KCD up to ~8.5)
Graphics? The pop-ins and rain (Missile Command and clear sky) are distracting and silly but aren’t functional so fixing them will undoubtedly improve the game but doing so won’t advance the game much towards a 10.
Design elements? Yes, absolutely.
Squad tactics and formation. NPCs act largely as individuals. And while that’s perfectly fine with bandits, soldiers should behave differently. Cavalry, infantry and ranged squads should fight as a team (form a line, etc) within which Henry can participate. Adding this element would be transcendent. Without it, it’s a bit like playing an ancient Greece game covering the Battle of Leuctra in which the Spartans and Thebans fight as masses of soldiers instead of phalanxes (trying to break/outflank lines.).
Units. Daniel mentioned limitations preventing the implementation of mounted units. Until these barriers are overcome, not having mounted Cuman (beyond Run quest) is a fundamental disappointment. It’s akin to the Soviets not having T-34s at the Battle of Prokhorovka.
Weapons. Crossbows, polearms, and maybe hand cannons. Again, there are/were technical issues. Not having the full suite of weapons used at the time isn’t a huge deal but it keeps KCD from perfection. [Not having crossbows and hand cannons as part of Hussite war carts/wagons (potential future game) would be a huge deal.]
Dynamic events. It’s nuance but having marauding bands of Cuman and bandits would add a much needed sense of instability. Having these bands attack the restarted settlement of Pribyslavitz would be a great confluence of play elements.