A 4.5-inch dual-purpose battery for Tribal-class destroyers

Would 4.5-inch guns improve the Tribal class enough to offset the reduced caliber?

Yes; a suitable 4.5-inch mounting would raise rate of fire and add strong high-angle capability.

The smaller caliber is offset by a faster, more versatile mounting derived from the weapon later used by the Battle class. Four twin 4.5-inch mounts would give the Tribals a high rate of fire against surface targets. Their elevation would also let the main battery engage aircraft from the outset. That capability avoids the later sacrifice of X mounting for a separate twin four-inch anti-aircraft weapon.