We're not trading 1% damage for 1% crit unless you have a very strange gear setup with 126 rating weapons and far too much crit. In Columi gear you're trading something around MAYBE 20 damage at most for 2% crit. The 15-20 bonus damage is a lot less than 1% and the 2% crit is actually about the same in terms of DPS value even after taking into account power modifiers on attacks.
its not just 20 weapon damage though thats what you do not see. Power itsel increases EVERYTHING including crit damage, crits only increase your chance to crit. so every time you do not crit you get nothing from it unlike power, surge is devauled even more because you must crit for surge to even be added to the equation.
Power will always be a better stat then crit unless you are sub 20% crit.
mathmatically something like crit will always have a diminishing return the more you get of it. A straight damage increase does not. I really do not feel like explaining all the math, but Crit is for people who like to see big numbers every now and again, power is for people who actually want to do solid damage ALL THE TIME.