Thanks to Bob Geier for this wonderful summary he posted on the Scout-L mailing list.
OK, so as a help to those who don't want to wade through the whole thing, I sat the two next to each other to summarize updates. The update list in G2A you'll find not particularly helpful, or at least I didn't; it also misses some changes that were made and references a few sections where no real change occurred. The archives has an analysis I did on the previous version when it came out a year or so ago, and I'll try not to repeat that work. I try to put changes into categories and highlight the most significant changes first, but that is of course a matter of opinion.
1. DE-EMPHASIS OF SKILL PROFICIENCY FOR ADVANCEMENT
Probably the biggest conceptual change is that this version of the G2A continues the departure from the BSA's Rules & Regulations with regard to expectations of learning and proficiency in skills. The consistent thread in the new G2A is not to expect skill proficiency to earn ranks or badges at the Boy Scout level, but rather approach proficiency through activities AFTER receiving a badge "earned" by fulfilling/checking off requirements.
This is reflected in a number of areas:
1) In "Advancement Defined" (220.127.116.11 & 18.104.22.168), the addition of a few paragraphs that suggest that retention should not be expected at the time of earning a rank or award, but that it is achieved through later practice and instruction in "real life" outdoor experiences. The implied message is that ranks or awards can be earned without retention, practice, or "real life" outdoor experiences. This is reinforced in the next section emphasizing the vague "personal growth" over both the learning and "retention" of skills. The claim being made is that getting an award develops confidence, and that's what's most important.
2) Elimination of longstanding wording to the effect that a badge recognizes what a young man is ABLE TO DO, rather than being a reward for what he has done. Instead, the new language is that "a badge recognizes the Scout has gone through an experience of learning something he didn't previously know. As a result, through increased confidence, he discovers or realizes his is able to learn similar skills." Thus CONFIDENCE replaces ABILITY in scouting recognition. This section also repeats the notion that "retention of skills and knowledge is then developed later [after being recognized for those skills]" through the natural course of unit programming.
3) Added text (22.214.171.124 box) that once a boy has been signed off by anybody, the requirement has been met regardless of whether the boy has learned.
4) Added text (126.96.36.199) "After the Scout is Tested and Recognized" This restates the new vision that "practicing skills in different settings and methods" "enjoying games" etc. occur AFTER recognition, not before. "The Scout fulfills a requirement AND THEN is placed in a situation where he has to put it to work." In other words, the vision is that Scouting recognition comes from box-checking, "confidence" comes from recognition, and only after recognition does a scout have to use the skill and build proficiency.
5) Added text (188.8.131.52) that changes from "A badge recognizes what a young man is able to do... it is not so much a reward for what he has done" to the new "A badge recognizes what a young man has done toward achieving the primary goal of personal growth. It is more about the learning experience than it is about the specific skills learned."
2. REQUIRING AND GREATLY EXPANDING THE ROLE OF A DISTRICT-LEVEL EAGLE PROJECT COACH
The former G2A contained 1 paragraph mentioning that many units/districts used Eagle Project Coaches, and a statement that they were recommended (but not required). The new G2A says that Eagle Coaches are "key to success". Rather than a few sentences of guidance, the G2A now enumerates a whole list of things that the Eagle Coach should do, down to reminding the scout to share his plan with the beneficiary and a number of other things that seem to move into the "adult directed" category.
What's more, the new Eagle Coach position is a district or council assigned position, which is meant to be IN ADDITION TO a mentor or advisor from the unit. So the boy gets two adults to hover over him, one Eagle Mentor he can choose from the unit, and one Eagle Coach that is chosen for him by the district. This also adds some delay to the project approval process, because when a boy submits a project for approval a council Eagle Coach now is supposed to contact him, set up a meeting, and go through another whole rigamarole before the project is approved. It is possible for the boy to refuse to work with the coach, but only after mandatory pestering by the district on how much "value" a coach can add.
3. ELIMINATING SOME UNIT-LEVEL QUALITY CONTROL MECHANISMS ON CAMPS/BADGE FAIRS
This edition of the G2A systematically eliminates the remaining unit-level mechanisms for quality control with respect to summer camp/ badge fair participation. This occurs in two primary areas:
T-2-1 Signoffs by Camp Staff
Section 184.108.40.206 authorizes camp staff members to sign off T-2-1 requirements for Boy Scouts. This contradicts the earlier section 220.127.116.11 and longstanding practice in the Scouting community, where camp staff could help a scout learn, but testing was reserved to the unit and those whom the Scoutmaster designated.
MB Approval by Scoutmaster
In the prior version, a scout was required to have approval from his Scoutmaster to begin work on a MB, and the Scoutmaster also had to approve the counselor and venue for the badge. This generally offered the opportunity for good counseling by the SM, as well as good quality control to prevent Dad from doing all a boy's MBs, or the First Aid MB done in 4 hours poorly at camp. In the new version, the boy only has to have a discussion with his SM, not the Scoutmaster's approval. And "the Scout must be allowed to work with the counselor of his choice."
4. ADDING A NEW UNIT-LEVEL PROTECTION AGAINST MB CHEATING
While the quality control mechanism of selecting counselors has been eliminated, the G2A has added a new section 18.104.22.168 which allows a unit leader to refuse to accept a blue card with a counselor's MB approval if it's clear that the boy could not have personally met the requirements for some reason. Retesting to determine if he actually learned the skills is not allowed, but inquiry into the circumstances of earning the badge is.
5. ADDED RESTRICTIONS ON MB COUNSELORS by Council or Scoutmaster or for certain badges.
* Councils are now authorized explicitly to limit the number of MBs one person can counsel, provided that the limits are not so stringent that they "serve as a barrier to advancement".
* Scoutmasters are authorized to limit the number of MBs each boy earns from one counselor, provided that the same limit applies to all the scouts in the unit. So this provides a generic, across-the-board mechanism for preventing Uncle Fred from doing all of a particular scout's merit badges.
* Added restrictions on who can serve as Archery MB counselors to match those for camp archery ranges.
* Added restrictions on who can serve as Kayaking MB counselors to match those for Canoeing.
6. ADDITIONAL EFFORT TO IMPROVE GROUP MB INSTRUCTION
* "Because of the importance of individual attention and personal learning in the merit badge program, group instruction should be focused on those scenarios where the benefits are compelling." So presumably, group instruction should only be used when "compelling".
* "Counselors agree to sign off only requirements that Scouts have actually and personally completed."
* "Counselors agree not to assume prerequisites have been completed without some level of evidence that the work has been done. Pictures and letters from other merit badge counselors or unit leaders are the best form of prerequisite documentation when the actual work done cannot be brought to the camp or site of the merit badge event." This is odd, because the added documentation seems to contradict the notion of a "partial" MB blue card.