I think this can only hold true when we're talking about ships within a relatively small time period. Otherwise we end up with modern corvettes that are far more capable then WWI era cruisers. Also capabilities and size are related. You can only fit so man VLS cells into a given hull and with the increasingly universal nature of these launch tubes, they become an ultimate limit on your ability to perform function A vs function B. The USN in many ways dodges the issue entirely by deploying a fleet composed mainly of very large destroyers and light cruisers with nothing particularly smaller or larger, making classification less relevant.
However when looking at other navies, be they French, British, Australian, or Russian, we have to consider that while the 22350 frigate carries 16 cells, it doesn't mean they consistently have 16 AShMs available. Size matters and an 8000 tonn destroyer with 32-48 cells of UKSK, plus a navalized S-400 would bring more then just double the size. It would bring the ability to conduct sustained strikes against land targets while maintaining an AShM arsenal.
How would this apply to Russia's 22350 frigates? They seem to have all round capabilities without anything being outstanding or lacking. Or am I missing something? They carry a SAM comparable to British destroyers, an AShM loadout that's smaller then that of destroyers but more capable then most frigates, and while anti-submarine warfare isn't my forte, they're pretty much the most modern asset Russia has in that department as well. Given the shortage of actual destroyers, we may well see the type fill the role of destroyers in future VMF deployments, escorting the Kuznetsov or future LHDs in place of the aging 1155s.
