Should you ever add aromatic veggies to a dish without sauteing them first?

If the recipes were truly interesting in 'releasing the flavors', they'd be sweating the onions, not sauteing them. Sauté is a higher-heat method that will cook the vegetables to create other chemical compounds, thus changing their flavor.

In the case of garlic and onions, this cooking makes them dramatically sweeter. But sometimes you don't want that -- you may want the sharp bite of the garlic, and to do that, you need to add it near the end of cooking, without it having been cooked.

Also of note is that if you are cooking in an acid (such as tomatoes), the acid will slow or possibly stop the vegetables from softening ... so if you want your onions to dissolve into the sauce, they need to be cooked first. If you them to add some chunkiness and the possible burst of onion when someone bites in, you want to add it later.

As others have noted -- in many cases, you'll add a given ingredient twice -- maybe some garlic to mellow out at the beginning of cooking, and then a crushed clove or two towards the end of the cooking.

That is really a matter of choice. If you cook the veggies for a while, they will also release their aromatics.... but they taste different. Especially if using onions. and especially if you sautee long enough to brown.

Not browning bones and veggies gives a light boullion, browning them a brown bouillon.

To give you an example: Marcella Hazan gives in her Classic Italian Kitchen cookbook different tomato sauces: 1) just chop an onion in half 2) dice onion and vegs but dont sautee 3) dice and sautee

In fact, to sautee or not to sautee is a great way of making dishes taste a bit different, while using the same ingredients. Nice for variation and for more refined combination.

And, yes, with saute I also mean "sweating".

Thai soups (Tom Kha, Tom Yum etc) are an interesting counterexample - where shallots, peppers, onions ... are just thrown in the broth in many recipes. Moreover, there are lemongrass, galangal, kaffir lime leaves and other more specialised aromatics that are almost never sauteed in these, even if the same ARE sauteed (as part of a curry paste) in other dishes.

Also, I have seen good dal recipes where onions, garlic, ginger are just thrown in with the rest and boiled for hours.

And garlic is not infrequently added late and raw to tomato sauces, in addition to sauteed garlic at the start...

EDIT: Frequently, aromatics added raw are crushed, likely so that some of the aromatic juices get expelled easier. Also, if they are themselves inedible, cut in such a way (eg fanning) that they stay in one piece but have maximum surface exposure (lemongrass and galangal, though I find milder/younger types of galangal deliciously edible when they've been stewing in the soup :). What not to do: Add vegetables the same color as whole hot peppers when you have sensitive guests, or black cardamon (more a whole spice than an aromatic) with raisins :)