Then the group finder is probably not for you. If you want to be selective about who gets what loot and why, shouldn't be using it. Run with a group of friends or guildies. Yes person who want what is in the item NEEDS it more than person who WANTS shell. That however, does mean they are more entitled to it. Person who needs mods could just as easily pull said mods out of another piece of gear. Where as person who wants shell can only get the shell from that shell. By that logic WANT>NEED. But I'm not trying to imply that, just saying both parties helped in the kill both have a claim to it and thats what the dice are for.
There is a reason you can't change the loot system in LFG. It has to be fair to everyone particpating. If a person doesn't want to pass on something they want because other person needs, they don't have to. It doesn't warrant a vote kick when thats how the system is designed.
I will however grant you one bit here, when you click on the dice they clearly say NEED, GREED, or X. Clicking the NEED button implies you actually need it and at least some of its components. Unfortunately there is no WANT button and most people greed rather than pass, so if you actually do want some of it NEED is what you are stuck with.