Captures is a poor stat to measure contributions. I usually don't have a ton of captures because I feel it's more useful to be a defense buffer between the guys who are capping the node (so the whole team doesn't get Nova Bombed) or continue past to apply pressure to a different node and hopefully split the opposing team's focus. Also in general a guy who goes 25-10 with only a couple captures but constantly sending people to respawn is helping more than the guy going 9-14 with 8 captures which probably means they are just immediately losing those nodes back.