Late answer but … better late then never
Anyway that’s a cool idea and better convention (mine was just example)
As for unit animations. If you really want to make moding vcmi easy then how about support for static (chess like figures/creatures). I mean from moding point of view making battle animation of creatures is the hardest and most time consuming task. On the other hand static chess like figures could also look good if done right … with some programable effect for taking damage and atacking like for example two sword crossing animation (or using the existent dread knight special animation)
just an idea which is not a top priority thing anyway.