I halved the recipe but kept the same amount of spices (so essentially doubled the amount of spice the recipe called for). As I let it cook in the slow cooker, i tasted it periodically and added salt, a few shakes more black pepper, and a spoon more of cumin and coriander powder. It got a really strong taste! I ended up adding about a fourth of a cup extra of water and a fourth of a cup extra of broth (I used the Trader Joes variety, which in my opinion is the best veggie broth that i've tried and has the least watery consistency).
Like me, you might have to halve the recipe (except for the spices) for it to fit in your slow cooker if you have a small one.
Highly recommend taste testing halfway through the cook time so you can add more spices to your taste/ more water. It does have a more stew like consistency, but it was really flavorful!!! I highly recommend you make it if you follow these modifications otherwise i'm sure it will turn out bland.
For more kick, add in a few teaspoons of crushed chili powder.