Interesting how this thread has developed. There seem to be two main schools of thought - one suggests that the RNR should be limited to tasks within its trained capacity, with the caveat that due to training limitations (time and money) these will, of necessity, be relatively low level tasks, whilst the other suggests that the RNR should be composed mainly of ex-Fleet personnel (in whom the training investment has already been made) which would enable the RNR to exist as a direst backfill to the RN in any role at any rank and rate...
Now, and I standby for the inevitable hammering I am about to take, lets consider training issues as they present for the RN (and I will limit myself to Officers). Training has, traditionally, been front loaded. The BRNC commissioning course, CFT and Fleetboard represent a lot of professional training loaded at the beginning of the Officer's career (about 2.5 years worth in fact). There are very good reasons for this. Roughly speaking, there is one term at BRNC to convert the civilian to the military way of doing things (+ leadership skills), there is one term to provide the base level of professional knowledge to act as a JO and one term to provide the wider management and "polish" expected of someone who will be representing UK PLC as and when they interact with the big wide world out there. CFT provides the LEGAL seatime required to obtain the STC95 watchkeeping certificate + practical experience at sea, working in what is for most people a completely alien environment when they first meet it. The Fleetboard is a check that the individual has completed this training regieme and is competent to operate as a JO.
If the requirement for RNR officers was identical, the training regieme would also have to be identical...say 33 weeks academic training and 12 months fleet time. I'm sure you see the problem - unless (like the US) you are willing to sponsor people through something like the ROTC programme then allow them to serve for a very short period at sea (3 years) it is impossible (ie UNECONOMIC) to even consider this type of training. For many years the RNR followed the system set up during the Second World War (I would strongly recommend the book "In Which They Served") which identified that BASIC officer training required about 18 weeks training - which could be spread out depending on the skill set desired. Working on the rule of thumb 4 weeks @ sea (inc weekends) and 2 weeks ashore it required 3 years to gain your Sub Lt. Similarly, it took 7 years (roughly) to Lt and a further 5 years (roughly) to Lt Cdr. Given a "career" of 16 years it can be seen that the training system was designed to provide mainly Lts with a smattering of Lt Cdrs.
The night of the long knives put paid to this system (which had worked reasonably well); the RNR became a niche service (with fairly ill defined training requirements) and problematic career structures. The numbers referred to in earlier posts, 87 Cdrs, 350 Lt Cdrs and 250 Lts are largely a legacy of the downsizing in 1994. Similarly, the current training regieme of 2 weeks (course/exercise) per year + specialisation training of about 2 weeks per year is a legacy of the financial restrictions placed on the RNR and the LEGAL decision that since it was impossible to fulfil the requirements of STC95 (under the version signed up to by the UK), there was NO WAY RNR officers (other than List 1) would ever fulfil posts requiring BWC etc.
One might lament the loss of core seagoing skills, but the RN made the decision that RNR officers could get by with the training they get - because in general, until fairly recently, they fill posts with no need for detailed knowledge of operating pussers war canoes...
In terms of rank - it really is irrelevant whether an RNR Cdr has the same "experience" as his/her RN counterpart UNLESS they are in an active command appointment at sea! Most RN SO1s fulfil staff jobs, and unless these are specialist (engineering/logistics) or operational biased, they are simply middle management roles which happen to be filled by officers in uniform. They require good staff skills and a degree of military knowledge. Most RNR personnel at SO1 rank are probably quite capable of filling these roles at FTRS/mobilisation as, based on their age, they are probably filling similar roles in their civilian employment! As has been pointed out, RNR SOs can attend the regular advanced staff course (if they are willing to enter into an FTRS contract to amortise the cost of the course. This is a very good management course (with a military bias) - IT IS NOT A "HOW TO FIGHT YOUR SHIP" COURSE. It recognises that SO1s will, on the whole, fulfil generic management appointments within the MoD.
Now, given the current desire to "change use" of personnel to get a greater usage out of the RNR can we change the training regieme to improve the skill set? The answer is, of course, yes - providing we are willing to invest in it. I would, personnally, like to see the training more biased towards JOs, with the old 4+2 system reinstated for A/Sub Lts and Lts (probably financed by a reduction in the training for Lt Cdrs and above). It would enable the RNR to grow limited seatime skills - but only if that is what the RN wants!
Just before I get off the soapbox, RFR...there is the thorny question of how do you use the RFR. This is a POLITICAL question - not one for the military manning system. How many of the ex-matlots reading this would be "happy" to be pulled back from their civilian job at zero notice for as long as the system needed them? The reason that the RNR is used instead is that the civilians have "volunteered" to accept that requirement (under the RFA1996). RFR recall requires the equivalent of the old Red Hordes coming...it would be a very brave set of politicians who enact the same type of regular recall requirement as the US operates (for example). We effectively shut down our ability to do this in 1958.
I apologise for the rant - I spent most of my military career as a Schoolie and have a relatively short fuse when training and the RNR are mentioned.
WE used to have, pinned in the office, the following statement which is well worth remembering:
"If you think training is expensive, try ignorance!"
Rant over - now retiring to the citadel to await the inevitable.