One thing I noticed is in the comparison tool it compares rings/trinkets in the order they are on the characters. If two people have 1 of their 2 trinkets the same as each other, but the other one is different, the comparison tool will not compare the equal ones.
Would be nice if it identified the same ring/trinket on both characters and chose to compare them to give a Difference of 0.
On the same level... A nice functionability would be if people could change items on the comparison or on the regular rating tool. In my case I left my Riding Crop on so I could change it to what I have to get a better idea. Or this functionability could be used to check how an upgrade would look.