Why does my curry taste so bland?
The recipe is easy on spices with (perceived) spiciness: No peppers, just the usual amount of ginger and only 2 cloves. On top of that, close to half a liter of coconut milk gets added, which will sweeten the curry, and dampen the (again: perceived) spiciness.

The main veggies are cauliflower, far from the most exciting taste in the world, and peas, which tend to have a sweet taste. 

Also, the amount of veggies (close to a kilo) compared to the amount of the spices seem a tad on the small side. 

Personal observation: I'd have to make it myself to see what (if anything) is missing, but as Chris mentions, some cumin (usually an equal or half part compared to the coriander) might help, as would nutmeg and/or mace, all of which (IMHO) go well with cauliflower. 

I've found that good Indian recipes are hard to find on the internet (or I'm not very good at searching). They tend to be of the Ginger-Garlic-Coriander-Cumin-Cardamom-Blended-With-Tomato-Puree variety, which although definitely tasty, all merge in to the same taste. Maunika Gowardhan has nice authentic recipes, and the slightly dodgy looking India Curry too, together with lots of spice mixes and background information.