I have never tried the crock pot method, but I think I will.
When I make pot roast I sear the roast on all sides with hot oil and chopped garlic to seal in juices (thats what mom told me) in the roasting pan. Then I add quartered onions and potatoes and carrots. (mom adds turnips-yuck, anyway)....I season with salt and pepper and garlic powder. I add onion soup mix (make according to directions) and sprinkle rosemary on the potatoes. Cover and roast in 425 oven first hour. Then turn it down to 325 for 4 hours.
~Out beyond ideas of wrongdoing and rightdoing, there is a field. I'll meet you there.~