I'm honestly okay with the whole Royal Sisters' retirement thing. I stress "okay" because there's a world of difference between that and outright liking it, I think. I know I wouldn't have done it if given the opportunity. I didn't like it at all at first, but I think after a while I realized that it was more because I felt it was too different from the status quo rather than any sort of story-based criticisms, and I've since made my peace with it. Besides, on a more positive note, it opens up more opportunities for my two favorite sisters. I wouldn't have made this group if I thought otherwise.

As for how it happened...well, I've seen the arguments, and yeah, I will concede that it could have been handled a lot better. I'm okay with it at the end of the day, but I still get where people are coming from.

I do not, however, think that Celestia was being some manipulative jerkwad in "forcing" it on Twilight. As one particular user commented:

If Twilight didn't want to take over, she would have refused. Twilight isn't a pushover, she never was, and acting like she has no agency to make her own decisions is taking her AND Celestia's characters way off kilter from how they have been established.

And they're absolutely right. Twilight could have refused, and if she'd said "no", then Celestia would have respected that. The real Celestia, not the "fascist" tyrant monster people like to paint her as.

I believe she picked Twilight because, for all of her short-comings and failings, she found something within her that she knew could be a great benefit to generations onward. Twilight's already proved that over the course of the show. And if the Equestria we see at the end of "The Last Problem" is any indication, Celestia's hunch was right. And hey, if Twilight does run into some snags here and there, then she'll always have her friends around to help her. They may not live in the same town anymore, but that's not going to keep them apart. And even if she does outlive them, well...they'll never really be gone so long as they're remembered (I, for one, am not a fan of those fanfics where they all kick the bucket and Twilight goes into a crippling depression. It'd be sad for her for sure, but I highly doubt it would be to that degree).

So, uh, there. That's my bit on the whole thing.

I rather liked the idea of the Sisters retiring, but that's largely because the impression I got from what little we got out of their backstory, they really didn't want to be Princesses. In fact, it was their role as rulers that caused their millennia-long fallout. No s!@# they wanted to bounce the second they realized Twilight Sparkle was 1) more powerful, and 2) smarter than they were.

The idea was there, but the execution left something to be desired. Celestia and Luna deciding to just retire out of the blue and hoof the reigns to Twilight unannounced feels wrong. And although they did back off on the initial plan, they still went through with the retirement idea that seemed to just be because they wanted to. I'm sure it's at least partially because they're tired of ruling and want to live like normal ponies, and they're confident Twilight can manage on her own. But the way the show went about doing it wasn't the best way of showing that.

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My personal headcanon was that initially their goal was to get Equestria into a decent place where it could run itself, and then find a successor(s) and step aside when they felt it had gotten to that point. Perhaps some time between that they got a little too involved, resulting in the whole Nightmare Moon debacle. Celestia waited the next 1,000 years for Luna to come back, and only started looking for a successor among her students (i.e. Sunset and Twilight) when the time of Luna's return was drawing nearer.

But that's just me.