I'm making veggie stock but I didn't saute the veggies first. Will it not be as good?

When I make stock of any kind at home, I use a pressure cooker. I don't want to waste waste money on letting it simmer for a long time. Bring to pressure for about 30 min. and let cool on the stove. Only use as much water as you want to end up with. There is no reduction necessary. It works out great and is a lot faster. For veg stock, I would leave them fresh or roast them for different flavor. I wouldn't saute them, because I like my stock to be as clear from fat as possible.

When I make chicken stock, I brown onions, carrots and celery first, but when I make vegetable stock, I like the stock to have the light taste of fresh vegetables, so I follow the rule of throwing all in a pot, adding water to cover and simmering for about 30-40 minutes. I usually use vegetable scraps, some fresh vegetables if I want a specific flavor to be prominent, fresh herbs, and garlic.

One trick for squeezing the veggies, is to use a potato ricer lined with with a couple of layers of cheese cloth.

Now use my potato ricer more for other things than potatoes. Including squeezing water out of cooked spinach or for making cabbage slaw where you salt, squeeze and rinse the slaw before dressing. (that tech prevents overly watery slaw).

Squeezing is the big trick here! I think sauteeing detracts from the purity of flavours you get from the throw-it-all-in-the-pot method

You should be fine. I always save onion, celery, carrot, etc, trimmings and put them in a baggie in the freezer. When I have enough I just dump them with any fresh veggies and aromatics into the crock pot and let it go 24 hours. Sometimes I'll make roasted vegetable stock which is a different critter but not as delicate in flavor. But I've never sautéed my vegetables first because I don't use oil or other fat in my vegetable stock.

No need to sautee veggies first. I always make veggie stock from Carol Gelles' 1,000 Vegetarian recipes. She calls for throwing all the veggies in a pot - it works great. Trick in her recipe is to squeeze all the juice out of the cooked veggies when done (and to cook for a long time.)