Even more news out of PAX from Respawn: the team is working on adding tweaks and variants to current Titanfall game modes for only limited time, like one or two weeks, to change things up. If fans respond positively, then the tweaked mode could become permanent within the game.
One of the modes they are currently testing, internally called “Attrition Elite”, tracks pilot and titan kills for score, but not AI kills. This is a middle ground between Attrition and Pilot only mode so it reaches more fans.
Respawn has said that this features are still in testing, and things can change anytime.