The point system doesn't make sense. Capturing points is the most important thing, second to killing enemies/surviving. A Support Champion can never get first place, since they don't get kills. Bot lane tends to just defend their CP, but because they aren't always standing around their CP, they aren't getting the 5 points.
TBH, just get rid of the Point System. Just use K/D/A and Neutralized and Captured Points. Since the 2 main goals of Dominion are capturing and killing the enemy, this clearly expresses your goals, and who on each team is doing what, and how successful they are.