I'm only about 12 hours in, and there are a lot of design issues I have with the title. The basic gameplay is fun, but the exploration is gimped with locked doors to prevent "screwing around" when we're supposed to "focus on the mission at hand," which is exactly like Metroid Fusion--and is something that is very much not the flavor of a Metroid game. The plot device of needing permission to use upgrades and items that Samus is already carrying? Let's be honest here, it's flat out fucking stupid. I welcome deeper plot and story exploration for the series, but this is the exact opposite. It's not deep, it furthers nothing. It's illogical, annoying, and foolish. It's also "Metroid by numbers" (which at this point will be the title of the review I write for a different site when I'm done) as it follows the same basic gameplay design with all the exact same items we've had before and really expands on nothing. The emergency "life recharge" is damn near a useless joke since all the bosses attack without pause, meaning it's next to impossible to pull off.
Sometimes, the writing is good, almost as if a western (American) studio had done it, but most of the time, it's ham-fisted anime-style melodrama, which is unrealistic and annoying.
My opinion may change towards the end, and keep in mind that I'm a HUGE Metroid fan--this is my favorite overall video game franchise (followed by Resident Evil), but so far, here's how it's panning out: Super Metroid remains the peak of the franchise, followed closely by Metroid Prime 1, 3, 2--in that order. I dropped MP2 below part 3 because the light-world/dark-world theme is a Nintendo cliche, most commonly plaguing the Zelda franchise.
While I am getting quite a bit of enjoyment out of the game, much of that is cancelled out by the negatives I listed. This may not exactly be an all-time low for the series (Fusion still holds that title as far as I'm concerned), it is the weakest console-based title.
Samus talking doesn't bother me. The ham-fisted, and occasionally offensive writing governing her actions on the other hand, have really gotten under my skin.