Why a full Aegis-like system would enlarge an ASW frigate

Would Britain equip Type 23, Type 26, Type 31, and Type 32 frigates with an Aegis-like system?

The full system is considered too costly and demanding for those frigate roles; combining it with a complete ASW suite would produce a substantially larger ship.

The Type 23, Type 26, Type 31, and proposed Type 32 are discussed as frigates whose design priorities differ from those of an air-defence destroyer. An Aegis-like system carries a substantial cost as well as a large computing requirement. Combining that system with a complete ASW installation would need more generating capacity and equipment space. The illustrative estimate adds roughly a third of a Type 26's size and power-generation provision to a Type 45, producing a ship in the region of 10,000 to 12,000 tons. Canada's River-class destroyers are cited as an example of the resulting classification.