Nintendo wouldn't have fixed what they couldn't. Seavor (Conker creator) split from the team because he ended up not getting along with most of them;

-Stamper brothers wanted to retire with fat pockets,

-Perfect Dark team had to endure a developement hell to ship the game in the conditions they didn't like (they split after that),

-Nintendo didn't want Rare making mature games. Nintendo didn't have as much input in Rare games like people are making it out to be. 

I believe you completely missed my point.  What I was saying was people think the old Rare would still be here if Nintendo acquired them, they wouldn't, that ship had sailed.  What Nintendo would have done most likely is hire new talent and rebuilt the studio entirely.  So there would be a Rare studio, it would probably be good, and they would probably have a similar focus by design, but it wouldn't he the old Rare.  

Rare is just a name, they bought the company and alot of people from Rare went away, the people and the company philosophy of 90s early 2000s does not exist anymore. Rare is dead and has been for a long time. Rare is basically a corpse that is being moved by Microsoft and acts like it is still alive.

Short answer yes. All of their big IPs are well known on Nintendo consoles. Sure some talent may have left, but like many have stated Ninty would hold their hands if they had to.

I'd argue that Rare peaked in 96-98, and then declined in 99 onward.

Even though their output was fairly high with 10 games in 2 years, and arguably with more polish, they did not have the same oomf of their earlier counter-parts; and replaying them years later, are just not as fun.

On their two big titles from this period: While objectively Perfect Dark and DK64 are more feature filled and polished than GE007 and BK, neither were as groundbreaking, they both lacked the pacing perfection of the predecessors, and the level design just wasn't as fun or satisfying. Micky Speedway was no DKR either. This wasn't a situation like DKC where the sequels were arguably improvements over the originals with even better level design.

Jet Force Gemini was the last somewhat fresh game they had on the N64 until their last outing with Conker BFD. Also, probably, their most underrated game on the console unless you speak with a Blast Corps fan.

I am guessing Star Fox Adventures is the spiritual sequel to JFG, but again, while it was more polished, the decline was obvious.

Conker's Bad Fur Day in 2001 seems more like an exception than a proof of their competence. It was more of an anomaly of fun and fresh feeling gameplay. I would hazard to speculate that the brilliance in that one is leftover from early times, the game was 5 years in the making.

Probably yes. But Nintendo sold them to Microsoft and killed them with this step. It's their own fault.

Sea of theives looks like a great game.

Nintendo never owned Rare, inform yourself. They owned a big chunk but then Microsoft bought most of the company and they let it go.

Obviously opinion is subjective, but I found Kameo and Viva Pinata merely okay, and Perfect Dark Zero and Nuts 'n' Bolts straight-up bad. 4th and 5th gen Rare had a real charm and creativity that I feel simply vanished from their games from Starfox Adventures onwards. They no longer had those "oh, that's so clever/cool" moments.

According to Rare's own "making of" featurette the game underwent a comprehensive redesign after the Free Radical guys left, so I don't think they can claim all the credit for the quality of the final game. Banjo Tooie and Conker, released post-1999, were also still good. It was Starfox Adventures when their decline began, in my opinion.

Nintendo wasn't happy with Conker as it was rated M on their console.

Nintendo already gor Mario, they don't need Banjo.