Great review about a restaurant!
I'm also a fan of Indian food and restaurants. You mentioned that the waitresses could smile a little more: I agree with you, however I don't know this place, but in Indian restaurants in Germany I experienced the same. This is their manner, this is how they are, but it doesn't mean that they are not friendly or happy about you. They are always very polite and look for your wishes.
As you mentioned the spicy meals, I think on the fact how the food cannot taste "real Indian" without spice! Also, it happens, we ask for light spicy food and we get an even spicier meal than normally. :)