But it wouldn't be. Without contact with the Founders, odds are that Odo would not have learned to shapeshift properly even if given centuries. He was stunned and delighted to learn what was possible for the likes of him in "The Search"; had he not shaken hands with a Founder, he would never even have dreamed of such things.
What about Laas then? He apparently never came into contact with the Founders, and didn't even know much about them until he met Odo, yet he was capable of taking shapes which Odo had apparently never even considered, and all through his own periods of trial and error. I agree that not knowing the Founders would reduce Odo's potential for growth (no pun intended
), but I'm not sure the odds would be so high against him.