I would be curious to know if “casserole” became a catch-all term in the States for people stirring random foods together and baking it. I have eaten an abundant variety of casserole (because potlucks were really popular when I was a kid and EVERY WOMAN BROUGHT A CASSEROLE) and there really doesn’t seem to be any rhyme or reason to it.
I’m interested in your less gravy stew. Does it come tucked inside a hot water crust pastry pie?
Actually, original casseroles were typically some type of veggie, or veggies with a starchy binder. Having lived in England for 7 years I find the American much less dense than the British! And by dense I mean ingredient-wise as Craic mentioned above. Maybe I've just always had an aversion to heavy meals, and remember the British as shepherd's/meat-type stews ( which is a different ballgame than casserole ). Being a vegetarian, the American was refreshing and seemed much lighter.
Take macaroni and cheese, for example, though it's just macaroni and cheese, it can be very tasty and creamy when you know how to prepare it. If it's dry it wasn't made right. Also, a various blend of cheeses kicks up the flavor. Lastly, you can throw whatever in there - if you love cheese and broccoli, this casserole is perfect for broccoli. Add a few cloves of garlic and it's top notch. Anything but bland mac & cheese. So, yeah, Americans perfect it per individual taste - there are certainly no limits when it comes to casseroles here.
Well, except maybe the kitchen sink.