You say that as if it's a bad thing . But no, it probably is for a mod like this that's already complex enough.Honestly i'd like to avoid using it, just because people eventually would have to install it as well
You could however, add some goblin spawns that could be worgriders. Something fairly generic, like "Goblin Skirmisher" and "Goblin Skirmisher Captain" or something. With BGSpawn, they just get normal goblin animations, but IA if installed later could give them worgrider and worgrider captain animations (it does this already for some other mod, I forget which).