Detailed version: everyone knows that the Stronghold's starting units have low HP and there's nothing to tank with. Boars perfectly fill this gap: they have 15 HP at the second level, which is one and a half times more than Wolf Raiders, and have 6 speed (which will be 7 with the specialization), which is exactly the same as Hobgoblins. At the same time, Boars are not an overpowered unit for the second level: the same Wolf Raiders, in exchange for 5 HP, have more speed, more attack, damage, and double strike, and also cost 10 gold less. But Boars will be available from the first day and will not require an upgrade to the building in the castle, and that's the point. That is, this innovation expands the strategic options of the Stronghold, but does not make it unbalanced. In addition, Boar Riders, being Orcs, fit perfectly into the Stronghold thematically. The main thing is not to forget to specify that they are considered "their own" when calculating morale. The mechanics that allow upgrading units with a specific hero are already implemented in the campaigns, see Gelu. So this innovation does not contradict the continuity in any way. And I think it should not be difficult to implement technically.
Detailed version: everyone knows that the Stronghold's starting units have low HP and there's nothing to tank with. Boars perfectly fill this gap: they have 15 HP at the second level, which is one and a half times more than Wolf Raiders, and have 6 speed (which will be 7 with the specialization), which is exactly the same as Hobgoblins. At the same time, Boars are not an overpowered unit for the second level: the same Wolf Raiders, in exchange for 5 HP, have more speed, more attack, damage, and double strike, and also cost 10 gold less. But Boars will be available from the first day and will not require an upgrade to the building in the castle, and that's the point. That is, this innovation expands the strategic options of the Stronghold, but does not make it unbalanced. In addition, Boar Riders, being Orcs, fit perfectly into the Stronghold thematically. The main thing is not to forget to specify that they are considered "their own" when calculating morale. The mechanics that allow upgrading units with a specific hero are already implemented in the campaigns, see Gelu. So this innovation does not contradict the continuity in any way. And I think it should not be difficult to implement technically.