Hubkarma is still there. To see it, open one of your hubs, and click on "suggest links" near the top in green.
When I first started writing hubs, I overdid Hubkarma. I got high marks on that particular metric, but the early versions of my early hubs were too cluttered. Then I saw the light, and cleaned them up.
These days, I don't pay much attention to my Hubkarma score. However if one of your fellow hubbers does as good a job on something, to which you'd like to link, as compared with everyone outside of Hubpages, then support the Hubpages team, and augment your hubscore at the same time!