After I played OOTM for a while, I can see why.
Since the shops are populated by troops, items and spells from the get-go (game start), I see no way to add some new in there through the save. Many games with DLC do not have the randomness this game provides, or they have a repetitive randomness (each time you visit a shop, it has different stuff), which would allow for DLC packs to be implemented with new items.
There is also the matter of overall runes received throughout the game and the lack of ability to re-spec. If they add more skills but the rune amount remains the same, one would feel at a strong disadvantage. Even if there is no level cap in KBCW (there wasn't one in KBAP either), the reduced amount of runes by 50% will make it very hard to obtain one or all of the newly added skills.
Also, if you already took all the maps, I'm not sure the game can just generate one somewhere, somehow, to get you to the new area.
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