Yes control is a kill based game. However it is also about control. The control points are point modifiers. The more you control the more points you score for each individual kill. So yea kills are very important. Yet if you have a teammate who also focuses on holding control points that can also be beneficial to the team as a whole. The only difference between a person with a high kdr and a person taking control points is location. The person taking control points let's the entire map know where they are. As the announcer tells if your losing a point. So the likley hood of getting killed is greater than if your running around getting kills. Yet if one person dies 6 times just holding 1 extra control point they have helped their team overall score more points as the whole. However at the end of the match they will be judged negatively on those 6 deaths.

Getting rid of K/D still won't stop the rage quitting stat padders. The only difference would be they would rage quit because their score sucks rather than they died a lot.