Your points are well taken, but look at the flip side: someone who is non-prior-service with no Intel experience going OCS, for example.
That person also gets no Intel training before they get to pin on the gold bars, and the major difference is that they're going active duty right away and will finish the same Intel training curriculum sooner. Granted, they will also be immediately immersed in the Navy environment, and there is no question that the landscape is different for someone coming non-prior into DCO vs OCS.
However, I would also argue that DCO for some of these same communities is naturally more competitive compared against OCS, if not only for the sheer difference in numbers of slots available. OCS has boards every month for (nearly) every one of these communities; some DCO communities may only have one board, sometimes even one billet in an entire fiscal year! In that case, I think we can agree that the person they select is going to be (or at least appear to be) eminently qualified.
Personally, I think DCO -- especially non-prior-service -- could stand to have more than a two week indoctrination. Perhaps there could be a separate track for non-prior-service. I also will stipulate that some people getting accepted into various DCO communities aren't already experts in their field, but may still have proven management/leadership experience, and many of these people are typically in their late 20s or early 30s.
Now from a practical standpoint, maybe some of the DCO communities with more billets don't end up with people with tons of leadership experience and expertise in the field. However, I'd argue that those populations are still statistically at least as good as, if not better than, populations from which OCS is selecting for the same communities. Don't get me wrong; I'm not saying anything negative about OCS selectees for these same communities; only that it's a numbers game. I.e., what I am saying here is that, on the whole, if someone is competitive and/or selected for a DCO community, I would argue that they are virtually guaranteed of getting selected via OCS for that same community.
So what's the difference? That those going active duty go through OCS, and then both groups end up going through the same training? It seems to me that, aside from the active vs. reserve path, actually going through OCS is the only real difference before pinning on the bars (and for those not familiar with DCO, you don't even go to DCOIC before getting commissioned).
So, I guess what I'd ask is this: assuming the candidates coming in via OCS or DCO are high quality in general, can 12 weeks at OCS really "teach leadership" to everyone who goes through it, any more than the DCO process attempts to take people with practical organizational experience (preferably including at least management/supervisory roles, if not "leadership", which I admit is a different beast entirely)?
Maybe it's just fair to say that OCS and DCO are serving different needs of the Navy. ;-)