So the Reserve is actually going to be more of a strategic reserve and actual combat capability than it ever has been? Sounds good, I like that. When I've finished my degree, I might think about re-applying for the Army (Reserve this time though).
When you say 'combat mass' in regards to the Reserves, do you mean the Reserve Battle Group integration with the online brigade?
While I think it's a shame that combat capability is being 'cut' somewhat, I can see the reasoning behind it, and if the issues within support can be mitigated by realigning personnel into other roles, I guess that is a reduction worth undertaking.
I guess we shouldn't get our hopes up for that much imagined fourth brigade...
Actually the reserve is moving from being a defacto strategic reserve (despite that not being a directed aim since at least the '80s) to an operational reserve, ie one expected to contribute to day to day operational outcomes, and not just wait for the 'big one'. This is very much a good thing, as when the reserve isn't expected to contribute outside of world war 3, it's very easy to justify a lack of resources, equipment and training. You can't get away with that if you expect them to be able to contribute to ongoing operations.
It won't be all beer and skittles however, as it means that the reserve will be very much tied to the force generation cycle for resources. This will mean that those fmns/units in the readying cycle will get lots of resources for training opportunities, those in ready will get some, but those in reset won't get much at all. It will mean there will be lots of reserve soldiers out there not doing much training for long periods of time, the impact of which is yet to be discovered.
As to how the reserve is contributing, there are lots of different ways. There is the reinforcing battlegroup, which was just tested on Ex Hamel with three combat teams. This will be raised each year as part of the force gen cycle and be certified with the ready brigade, and be kept on a reduced NTM during the ready (albeit, much longer the the ARA).
There will also be a liberal amount of directed gap filling of ARA units, where manning caps have left holes in ARA capabilities. A good example of this is recon scouts for the ACR. The reserve will train up a troop of scouts each year, which will be integrated with the ARA ACR for Ex Hamel, and then be able to be called on during he ready year (again, at a longer NTM than the ARA). Similar things will be happening with engineers and gun regiments and CSS units.
Another way the reserve will contribute (at least in theory - it may never be tested) is by replacing ARA subunits on extended deployments. Analysis has shown that the current Beersheeba brigade doesn't have enough combat mass for success during a large contingency (essentially it only has seven manoeuvre sub units, it really needs nine for three full battlegroups). What will likely happen for the first rotation for a large contingency, is that the ready brigade will steal from the reset brigade to make up this necessary combat mass. The reserve will the be expected to fill these gaps for subsequent rotations (ie, will have 12-24 months to train up to the required standard.) Sounds good in theory, the practical application may be difficult without formal mobilisation (a 'call up', not merely a 'call for').
It's also a bit unfair to say that combat capability is being cut, as these changes are designed to increase combat capability. All that is happening is a rebalancing of personnel away from the manoeuvre forces towards the combat support force. Total manpower is still growing, not shrinking, it's just not going to grow as large in some areas as others. For example, there will still be a third tank squadron raised, which takes about an extra hundred personnel, and even under the best case the lift squadron will have to grow by >40 personnel when Land400 comes online. However, all those new capabilities have to be manned as well. The army is trying to build an army for the next war, and not the last one, which is a nice change.