Probably more, given your magnificent planning!
Hundreds if not thousands of people have already written about this chapter, but well, I want to too. After all, it's something I've been following ever since 2003/4, when the first anime series started airing. Started reading it around then too, though I lost interest for a while when the story meandered in the middle. But I picked it up again a year ago, shortly after the new series started, and never looked back.
I'll be honest, I quite liked the first anime series, but it's hard for me to reason why now. Perhaps I just liked bittersweet endings...? But in hindsight, knowing now what Arakawa-sensei planned out for her characters right from the start, I can completely understand why a lot of people really disliked that first series. Whilst the action was good (for the time), and some of the original material was quite creative (e.g. linking the homunculi to failed human transmutations), it didn't really make sense, both in terms of the universe that Arakawa-sensei created and in terms of the characters.
So, what about this ending then? There is some discontent, mostly centered around Mustang getting his sight back (via the philosopher's stone that Marcoh was holding on to), lack of Royai, and the general happy feeling of the ending. And I agree that the most sensible response to these people is to ignore them: they'll grow of of this "Yay! for depressing endings!" soon enough.
To me, all the choices made by the characters in this final chapter made sense.
I'm really glad that Al got his body back - this was the whole point of their journey, after all. And the great sense of responsibility that he feels for the people who have been affected by alchemy. Al-May official? Definitely, especially since he went over to study alchemy in Xing.
Like his father noted, Ed, knowing what it was like to be alone, would never have subject his brother to that. Nor would he have broken his promise not to use a philosopher's stone. Instead, gave up his Gate of Truth, and thus, his alchemy. For someone of his caliber, it's a huge loss, but as Ed has learnt in the course of the series, there are far more important things in life. Though it is apparent that he still involves himself in research so that he too can help the many people whose lives it has affected. And that proposal was probably my favourite part of the whole chapter - perfect!
Ling and Lan Fan learning more about the importance of friends, family and responsibility. I like how Arakawa-sensei links their experiences throughout the manga to their final decisions.
And Mustang...a lot of discontent surrounds his decision to use the philosopher's stone to restore his sight. Why? Because Ed and Al didn't? Because he would then have needed to rely on Riza forever? But that doesn't fit with Arakawa-sensei's messages throughout the story. Firstly, human transmutation was forced on Roy against his will, dealing him a punishment that he didn't deserve. Secondly, Roy's character has always been defined by his desire to make up for his sins in the military, especially in Ishbal. How would he have been able to do that without his sight? He would have been discharged from the military, and the trust that all his followers placed in him would have dissipated into nothing. The more power you have, the more responsibility you have...but conversely, you need power to fulfil those responsibilities. It is far better to have Roy working to change the country, as per his ideals, than to have him looking for some way to be useful as a blind person. I'm sure that the souls used to restore his sight would have been satisfied.
Oh, but I could have done with more Royai too, Arakawa-sensei!
p.s. somebody enlighten me, why "Royai"?
p.p.s. nvm...google says its from the Japanese combining "Roy" and "Hawkeye"...it helps that "ai" is a pun for "love"