This rating is based on simple arithmetic/statistics and not taken the situation under which these players scored / taken wickets. There should be some mechanism to include this factor for a real valuation/rating otherwise we can see these types of skewed results.
The ones above Kohli Ban, Eng, NZ have completed their 4 games.
Stats may change after todays match.
As for AUS, watson and maxwell bowl and bat hence their mvp rank will be higher than kohli as kohli only bats and doesnt hit big quick sixes like them.