If it was just hitting I would define it as number of expected hits to occur in the game given correct play.
For hypergammon it makes sense to look primarily at hitting; there is precious little blocking in that game. I calculated the expected number of hits of every hypergammon position. Your position,
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when played out cubelessly, averages 7.39441 hits. That's substantially more than the hypergammon starting position, which has 5.60538 expected hits.
The position with the most expected hits is the following one, at an expected 8.41680 hits.
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