For every +1 we can stack to crit range, the weaker Champion becomes because the relative increase get smaller. Going from 20 to 19+ for crits is a 100% increase. But from 19 to 18 is just 50%. 18 to 17 is 33,3%.
Champion might be the most boring subclass, but this is a really odd way of evaluating an ability. You might as well say HP, ability score, or spell slot increases are weak because each one is a smaller relative increase.
