Why a cruiser needs a helicopter

Would the absence of a helicopter be a problem for a modern cruiser?

Yes; a helicopter is a highly useful general-purpose and anti-submarine asset, and a hangar makes that capability sustainable.

Helicopter support is an important baseline for a modern general-purpose warship. A helicopter extends anti-submarine work beyond what the hull can do with its own sensors and weapons. It also gives an independently deployed ship a flexible asset for tasks that cannot be predicted when the vessel sails. That is why the lack of a hangar remains a meaningful weakness even on an otherwise capable cruiser candidate.