#6 Kemar Roach - West Indies
West Indies were considered the dark horses for the tournament as their players were in good form heading into the World Cup. That was evident in the very first game as their bowlers bounced Pakistan out for a paltry total.
But they couldn't retain the momentum as they suffered multiple losses after that.
One of the primary reasons for their slide was that their most experienced fast bowler Kemar Roach was absent from the starting XI. Roach had a great start to 2019 as he bowled Windies to a 2-1 series win over England in the Tests. But he didn't find favor with the management for the ODIs; others were preferred ahead of him at the start of the World Cup, and they failed to deliver.
In the limited opportunities that he got, Roach was excellent with the new ball; his economy of 3.67 was the best in the tournament (minimum of 3 overs). He picked up crucial wickets in the matches against India and Afghanistan, which restricted the opposition.
Windies lacked that incisiveness in his absence as they conceded plenty of runs in the middle overs and hence lost to Bangladesh and Australia from winning positions.