I totally agree mate^^
and the dissapointing results arent so much on the final size of the plants, but rather on the final yeild
I couldnt get 18" outdoor plants to yeild more than an ounce and every harvest i kept wondering..."what am i doing wrong..?"
From my (small) experience, small plants in big pots, do eventually explode in growth (after they develop a descent root ball) around week 3-4.
But, by that time, their properly repoted cousins, could be 30-40% larger in size and with much thicker stems and healthy branching. Not to mention a much stronger root system
Of course -as we all know- other variables play an equally important role for a good root system like good draining soil, proper watering, complete wet/dry cycles, root stimulators, pot/root temps, etc.