Welcome news! Thanks for sharing the details.
I have to believe that 90% of GMAT test-takers will now choose to put Verbal and Quant (either order) at the beginning of the test, since those are the only two subscores that contribute to one's 200-800 composite score. In my opinion, that's the way the GMAT should have been structured all along.
For me, Verbal/Quant/IR/Essay would be ideal, since I've found over time that the last part of the Quant section tends to impact my score less than does the last part of Verbal--in other words, the Quant algorithm is more "adaptive" than the Verbal, which requires a solid performance deep into the test for a 40+ score. The ability to complete the Verbal and Quant sections during the first 2.5 hours of the test, while I'm still sharp mentally, rather than 4 hours deep, will surely prove advantageous. Maybe now I can finally earn my perfect 800! Or maybe not. Hehe.
In some ways, this announcement has turned the GMAT from a 4-hour test to a 2.5 hour test. The exam should become much more manageable now, and I expect a lot of re-takes as a result. I also expect average composite scores to go up, though IR and AWA scores may drop concurrently.
It is also important to note that these updates to the test will make the free GMAT Prep software and Default Exam Pack much easier to use for practice (as opposed to diagnostic tests), given the large number of questions available in that question pool--
around 1,500 total. Instead of having to click through the essay and all the IR questions (not adaptive, and the same 12 questions every time) at the beginning, you will soon be able to proceed straight to the Quant and Verbal, and let the adaptive nature of the test take its course, guiding you to new GMAT questions every time, albeit with significant question repetition after frequent re-takes. Keep in mind that there are only 90 questions per test, but more than 15 times that amount in the overall question pool.
For now, however, the GMATPrep software has not yet been updated. GMAC tells us that GMATPrep will be updated with this "select section order" feature by July 31st, 2017.