So I've met Quiet Robe. I'm...extremely mixed on this.
From a writing perspective, this is a blatant info-dump with a character that's had no introduction, and he's promptly killed off as soon as that introduction is given. And poor guy, Samus really doesn't give a shit after looking at his body. The second living chozo she's seen since the Zebesian chozo were wiped out, and one apparently of the same tribe that raised her, and...yeah, she doesn't care.
On the other, the revelations as to what Raven Beak and the Mawkin were up to, plus the notion of an X disguising itself...these are nice revelations. It arguably ties in with the wider series as a whole, the idea that multiple groups have tried to control the metroids (the Space Pirates, the Federation, the Mawkin), and each attempt has ended with failure. For a series that obstensibly takes inspiration from 'Alien', it's an idea that's rue to the source material.
Oh, and that chozo robot. Yikes. Fun, but yikes.
I know Ridley's dead, but by the time of his final death on Zebes, he's been 'killed' four times prior, and there's nary an explanation to be had as to why. Nor is there any in-universe speculation as to why (as far as I'm aware).
I don't think Mother Brain is as egregious as the others, as being a machine, it's easy enough to say that she's repaired, but what's Ripley's excuse? And if, by Samus Returns, Samus knows that Ridley keeps coming back, maybe leaving him on the surface of SR388 wasn't the best idea in the world?
But heck, at least we know how Ridley was cloned for Other M, and by extension, how the X copied him in Fusion. So what's the excuse for Kraid? Because if he can survive a planet blowing up, then Samus shouldn't be able to scratch him.