Well yeah, but that's a set amount for all Skraelings with the building, where-as the Beothuk lands would be economically much weaker than the Abenaki tribes. Population-size would mean more significantly settled areas (Holdings in this sense). They wouldn't have a lot of them, and would still be poor compared to bad European provinces, but there shouldn't be artificial modifiers to regulate how Natives behave. They wouldn't be made unplayable, so naturally a human should also be able to make the homeland worthwhile.
A thing I'm hoping to do, though, is setting provincial modifiers for X number of years (the number gets higher the further away from the Norse settlements you are) that drastically cuts available Cavalry to field. Horses were, after all, introduced to America via European settlers, so it'd take a long time before they started getting cavalry (So you'd have 2 modifiers, for example, that together make you have 0% Cavalry. One runs out sooner and after that you get 35% of the total and once Horses are commonplace enough the limitation disappears).
Something else to toughen them up would hopefully be that the earlier the starting-date the less unified the tribes are, but as the Vinland colonies grow in power the tribal confederations should start to tighten around them. Might not have mechanisms in place for it during gameplay yet (apart from natural blobbing), but it should at least be there in the History.