Though I'm am interested in why they changed the design of her ship?
It's the design from Metroid Prime 3.
Four basic reasons:
1) Instead of making this, they could have made something good. We could have had a good metroid game rather than a terrible one. Nintendo has finite resources. They used a great team (NLG) for years... to make this.
First off, have you played it? I haven't. And even if you have or will and you end up not enjoying it, someone else might have a blast with it (no pun intended). I remember some Metroid fans raging that Hunters wasn't a "proper" Metroid either once, yet there was a very passionate community of Hunters players that adored the multiplayer (myself among them). This could very well scratch an itch certain players need scratched, even if you don't share that itch.
2) This isn't a spinoff in the classic sense of say, a Metroid Prime Pinball or a Mario Tennis. The gameplay here is the exact same style as Prime - it's clear that this could have been an actual Metroid game if they had wanted it to be.
Not really. From the demo, it has a moderately similar control scheme to Prime (and hence is a "Prime" game in that regard), but it's got enough differences to warrant it as a spin-off in the same way that Halo: ODST is similar in gameplay yet still clearly a spin-off with a lower budget and limited scale. A spin-off can still share gameplay features, after all.
3) Every bad game (including spinoffs) in a series affects a franchise. It affects the way you think about it, the way you interface with it. Bad games sell poorly and hurt the chances of games in that series. They hurt the prestige and mindshare attached to a franchise.
Then the fanbase can get over themselves. EVERY franchise has bad installments. Final Fantasy has All The Bravest, Mortal Kombat has Special Forces, Tekken has Death by Degrees, Devil May Cry has DMC2, Soul Calibur has SC: Legends, Mass Effect has Infiltration, etc.
And we're in a post-Other M Metroid universe. Really, that ship sailed a long, long time ago. I say that as someone who hates Other M more than any other game on the planet. We survived Other M; we can survive a middling portable spin-off title.
4) We haven't had a good Metroid game in a decade, and this game indicates that Nintendo doesn't listen to Metroid fans, has no idea what they want or perhaps doesn't care what they want. All of those things are painful.
NX. Patience. Wait.... Nintendo isn't talking about ANY of their major plans for ANY major series outside of Zelda right now. Metroid isn't some special little snowflake in this regard.
And portable systems have always been the home of experimentation and wacky ideas that don't always work, whether it's 3-player Zelda or multiplayer death arena or pinball Metroid or rumble cart Pokemon or Mario painting simulators....
That's because Mario, Donkey Kong, and Zelda are still alive and well.
We haven't gotten a single new Metroid game since Other M six years ago, and arguably a single new good Metroid game since Prime 3 nine years ago. The first new Metroid game in YEARS is a co-op shooter with a horrendously awful art style, with absolutely no evidence of any other "true" Metroid game in development. So yes, Metroid fans are pissed.
Then that's a complaint with the wait between proper installments, not the prospective quality or lack-thereof of a spin-off title. Federation Force's existence has no bearings one way or the other on the wait. Complain to Nintendo about that, but that's not Federation Force's fault.
And, again, you all make me feel OLD. There was a time where I got 3 Metroid games in 16 years, and that was then followed by an EIGHT YEAR BREAK.
And after that eight year break? ... we got possibly the best Metroid ever. If a Federation Force had dropped between then, I wouldn't have minded then either.