Would you like an in-game parser?

[Jynx]

I think that if they saw their DPS, and the group can see their DPS, they would be more obligated to improve. You can make the argument that they are lazy now because no one can see how they're performing. If an official parser was introduced and the lazy players were still under-performing by a lot, well then the rest of the group knows who to kick.

Has it ever been difficult to tell who isn't pulling their weight?

Unless your pushing bleeding edge content I'm certain that most content of the game the entire party can be semi-afk to complete. So in the end how does this effect anyone even if you have a metric to measure people. What does this matter to the "Bads" everyone likes to say they would immediately boot if only they had a number to throw in their faces!

The duty finder will still be plagued with lazy layabouts because they don't care what you think, they don't care if you have a number to judge them on, they don't care because they wont ever see you again nor will you remember them if you mysteriously actually see them again.

The only content this could effect is people pushing bleeding edge content and honestly a vast majority of those people use better tools than anything SE will cobble together.