Allow players to sort their achievements between two separate lists
Give players two separate achievement lists with separate gamerscores, a "Showcase" list and a "Dump" list.
Both lists should be visible for other players of course but now it is obvious which games that inspected player cares about.
The player should be able to move games and their corresponding gamerscore between lists, but the "Showcase" list would be the focus for people that care about percentages and the like.
It's in someway the same principle as a second profile on your box, just more user friendly.
All the data is still unchanged in the XBL profile, it's just a modification of how it is displayed.
This way, nobody can claim awesomeness for a 100% gamercard because the dump list still shows the complete story.
A gamercard could show, for example, an 89% Showcase with 242k GS and a 19% Dump with 1037 GS.
There can still be an overall combined ratio for statistics etc.
We also need a seperate list example base game 1000G then another list for the DLC, just like PlayStation, i love that feature.
Silver Mitsuki commented
This. I keep saying that we need this so much, why don't we already have this? Please Microsoft, we really need this, I never played a lot of games I wanted to try because it would annoy me so much screwing up my completition rate, I need this so much, I want a "Dump" category where to throw all the games I don't want to show publicly.