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.
It's a tired and goofy way of trying to use numbers to say a lot of nothing.
Simply put, the Champion has an increased chance of getting a crit. The additional gear helps the Champion achieve that goal. There are *multiple* ways to stack damage dice and create advantage that help the Champion.
Yes, other classes can try for the crit build, but they'll never be as good at it as the Champion, and they're likely opting for other builds anyway, meaning they're using those item slots for other benefits.
