Someone has published two unusual articles at "The Strategist", the MilBlog of ASPI (Australian): He argued not in favour of classic warships, but of land-based naval capabilities and short-range boats. His idea was that the Royal Australian navy shouldn't pay so much attention on what it can do ion distant waters with warships, and pay more attention on how to protect Australian maritime trade where it's the most dense and thus the most vulnerable; close to Australian ports.
He apparently did so with commercial interests (PR) in mind, but these articles are nevertheless very unusual. Most of the naval debates are driven by shipyard interests, naval bureaucracy interests (preferring a large active force with many ship hulls and many jobs for senior officers) and navy fanbois with a focus on ship hulls as well. All three groups of usual suspects want warships, warships, warships - and preferably large expensive ones for distant waters.
Attention to home waters is left to a small bunch of Coast guard fans (salute to Chuck!).
I'm mostly sympathetic to Mr. Morrison's two unusual naval-themed articles, having published something similar a few days earlier.
He did a mistake (or omission), though: It's not that difficult to find and track ships on vast oceans after all. Sure, a few diesel submarine would have a difficult job there*, and even the increasingly unaffordable nuclear-powered attack subs are poorly suited for sustained wartime naval blockades on high seas (too few torpedoes and missiles aboard).
There's one unconventional solution that might make an ocean very unsafe, though:
A warring state could outfit a small container ship with some prepared containers, land a chartered (or stolen) helicopter aboard and then if would possess a modern armed merchant cruiser. This could even be done by clandestine services with personnel which turns into uniformed navy personnel only after leaving a neutral harbour. Such a helicopter-equipped merchant cruiser / commerce raider could detect and identify ships in a radius of hundreds of nautical miles and board (then burn or scuttle) ships with a fast-roping boarding squad at will. The expense would be minimal and a lot of patrolling/hunting, defensively armed merchantmen or a convoy system would be required as countermeasures.
This would still not necessitate destroyers with a price tag of billions or racing frigates with a price tag not much shy of a billion, but it's still something a serious "we protect our nation's maritime trade" navy should think about in advance.
I 'feel' the European navies are obsessed with maintaining a wide range of different missions and ship types (maintaining "competence" in ASW, AAW, MCM, subs etc.), with some at least small great power gaming intervention skills (mostly France and UK, but also to a lesser degree Spain and Italy) and in the case of Germany there's a post-2000 obsession with UN naval embargoes and similar patrol missions.
The USN meanwhile is obsessed with patrols of carrier battlegroups in distant waters, the ability to bomb the other countries and with preparations to defeat the IJN again.
Hardly any navy is focused on securing maritime trade near its nation's ports.** This is odd; it should be considered to be the second-most obvious job description for a navy. Well, it's odd until you think of a navy as a bureaucracy with its own interests and will.
*:He even claims "only long-range nuclear submarines will be able to patrol these areas". I'm always amazed how many anglophones have forgotten that conventional submarines ceased to be mere coastal assets more than a century ago! All those USN and RN nuclear subs and the marginal role of SSKs in anglophone countries have warped perceptions quite a bit apparently.
Germany's Typ IX D2 submarines of 1944 had 31,500 nm endurance (at 10 kts) already, and Japan's I-400 class in excess of 37,000 nm. The modern Type 214 wasn't designed for extraordinary range, but still exceeds 10,000 nm endurance.
**: Even Taiwan's and Japan's naval forces don't focus on this. I suspect Pakistan's navy comes close, though.