For all intents and purposes the Mogamis are filling the old tier 3 / OCV / corvette gap. What we are missing is the appropriate tier 1 and 2 mix.
I get where you're coming from Volk, but to be honest:
1) The Evolved Mogami is much more capable that the old Tier 3 proposals, and sits much more comfortably in Tier 2; and
2) I'm not convinced that a Tier 3 combatant is necessary. I don't think we can get something that has the range and firepower needed to be a proper combatant in our context in a sub 4000t package.
I think instead there is a much better case for leaving the Arafuras / Capes to the constabulary / patrol role (and potentially transferring them in their entirety to the ABF), and leaving the RAN to what it should be - the nation's battle fleet. And we should be focussed on right sizing the number of proper combatants that we're building.
For me the logic of the force structure is pretty simple - what is the operational effect you want?
My very much armchair view is if Australia is serious about simultaneously securing its SLOCs, protecting amphibious forces, and projecting power into the South Pacific, eastern Indian Ocean and northern archipelago, then the RAN needs to be able to put to sea, at any given time, the equivalent three credible surface action groups, comprised of a DDG, FFG and 2x GP frigates (plus SSNs obviously acting largely independently, besides maybe escorting a large amphib group).
If you accept that requirement the rule of three drives the rest. If you want 3 SAGs, you get to roughly 9 DDGs, 9 Hunters, 18 Mogamis and 9 SSNs.
That is why I think the official plan is still too thin. The current trajectory gives us 6 Hunters, 11 Mogamis, and a future replacement for the 3 Hobarts, within a force centred on 8 SSNs. That is a meaningful improvement, but it is still a fleet sized more for selective presence and denial than for sustained control of our approaches and persistent escort depth.
The real problem with the current numbers is not that they are “small” in a peacetime sense. It is that they are brittle in wartime. If you start with only 9 Tier 1 escorts in total, for example, the available force shrinks very quickly once you account for maintenance cycles, training pipelines, refits and battle damage. A force structure like the above gives you enough mass to absorb those normal losses of availability without collapsing the whole operational concept. Not because it sounds neat, and not because bigger is always better, but because it is the point where the RAN starts to look like a navy that can sustainably generate combat power in multiple theatres rather than just assemble a respectable looking order of battle for a one off engagement in one place at one time.
The other reason I like this structure is that it maps well to a continuous build. It's not fantasy fleet stuff. It's upping the tempo and committing to orders on existing programs for the long term. It would take us 30 years to get to this mass, but once we're there we would have a tremendous national asset, and for not much more (single digit billions p.a.) than the current plan.
If the future DDG is a Hunter derivative rather than a completely separate design, that gets even better. The yard is no longer switching between unrelated classes, it's building variants of the same family. Same broad production philosophy, same workforce, similar supplier base, similar combat-system spine. The Yanks have done something similar well with the Burke model of flighted evolution over decades.
Perhaps I'm missing something, but our current plan, where we might be able to muster a DDG, 2 FFGs and 4 GPs if we're lucky, simply isn't sufficient.
