2D-assets in 3D-view

[Gors]

Wouldn´t it yield an authentic appearance of an 2D animated movie, which could add to the experience of the game? It would certainly be unique, and is financially sustainable using drawing tablets.

no, it would not

it would look like ass because of a very specific reason:

1- games account for all kinds of events and thus the animations must be simplified and only have the necessary.
2- having lots of drawn frames will over-specialize the animation and thus be extremely tedious and require way too many man hours for even 3 minutes of "gameplay".
3- enjoy paying like $500 for said 3 minutes of game

this being said, either you want a fully 3D game with a 2D shader, or you want pain and suffering of all the chinese subsidiary animators