Making a placement based solely on one data point is moronic. They were right to not have done it. It is bad science. The difference between that system and the one in 3 was that there was not a linear progression up to the point that it would place you--you had twenty, thirty, fifty games under your belt that the system could use to determine what the next progression was as you approached your ideal skill matching point in Halo 3. This isn't the case in Arena, and that it needs 20 full matches to do it accurately is telling, and not without purpose. The game, after one match, would and should literally not have any idea where to place you since it, if it deserves to exist, wants to make sure it's not going to place you in onyx for crapping on a bunch of recruits and then have you swing to bronze the next game when you are matched against someone who has actually played the game before and lose.