Come to think of it I dont know why fire/dark would be to "strong" that early on in the game. I kinda understand why they might not want to use that typeing for starters, but I dont seem to see why that wouldn't work, especially since the starters would be fully evolved usually mid point through the gym battles, like 4th and 5th gym leaders, depending if you train your starter in the grass so the gyms are easy. By that time you would have already encountered dark type pokemon. So I actually think that having Enbuoo as a dark type would have worked just fine.
Come to think of it... you encounter Dark type Pokemon pretty early in this game... The purple Cat and Dark/Ground Crocodile. So yeah, I agree a Fire/Dark type as a starter would have been just fine.
In the end, there's nothing we can do about this guy though. I've come to terms with it's typing, and I'm enjoying using it. All we can do is hope the next one will have a cooler typing. :P