Ahhh, doctrine mongering.. where is my old DS hat? Here it is, under these empty beer cans and pistachio bags...Oh, wait--that's a dunce cap...
I think part of the problem is that we have a mix-up in terminology, or maybe in useage. "Doctrine", at least as I understand it, concerns itself with fairly broad things such as "Infantry and Armour Will Cooperate in Offensive Operations" or "The Force in Place Will Provide Fire Support for the Assault Force".
Fairly high level stuff that is based in common sense, doesn't really have to be changing every five minutes, and provides for a common start point for understanding. After all, if you're going to change the way you conduct a type of operation, its useful to know the start state you're changing from.
IMHO, doctrine allows people who don't always work together to have a shared idea of how to go about something. It's a guideline, not a set of handcuffs. Armies that treat it as the latter probably won't do well.
Also IMHO, what happens at unit level and below, is really much more about TTPs. TTPs can and should evolve very quickly (even during an operation) and will always change with the type of equipment and weapons, the training level (Kitchener's New Army couldn't be relied on to do what the 1914 BEF could do...), nature of the enemy, etc. TTPs may vary from unit to unit, and to be honest I don't think it makes all that much difference if they do. So what if 2 RCR does a BG attack different from 1 PPCLI? As long as the actions of the unit conform to the higher commander's intent, and are coordinated with whoever cares, so what?
The "Main Effort" discussion is an interesting one. I always taught that ME (at least at the Op/Tac lvls) is best expressed as "Somebody" doing "Something".
IMHO, ME is about achieving the critical result (or effect, if you want..) that is necessary for the success of that particular part of the operation. If you can't achieve it, that bit will fail and, quite possibly, the entire op will fail.
So, by identifying "somebody", you do two things:
a) tell Bloggins that it's him and his force that will achieve that critical result; and
b) tell everybody else that Bloggins is "it", and in the failure of any further guidance tey will act to support Bloggins in his task.
By identifying "something", you tell Bloggins (and all the rest of them) what it is that must be achieved. This gives Bloggins a good idea of what his most essential task must be, as opposed to magically divining it, or inventing his own that doesn't support the bigger picture. It tells everybody else what the task is, so that a) they can take it over if Bloggins and Co. get waxed or b) they can understand best how to support it.
So, IMHO it's not "In Phase 1 Main Effort is the Bridge at XYZ"
It's not "In Phase 1 Main Effort is 2 PPCLI"
But it probably should be "In Phase 1 Main Effort is 2 PPCLI capturing the Bridge at XYZ"