What track record of this do they have prior to 2014? It honestly seems like a stretch to get all of this out of a few years, especially if they were working on more than one game.

Indeed. Maybe this was the reason for that.

To be fair, from Prime onwards until TF they had a good record:

2002 - Prime

2004 - Prime 2

2007 - Corruption

2009 - Prime Trilogy

2010 - DK Returns

2014 Feb - Tropical Freeze

Very good to me. It was since TF that everything went dark.

I dont think they do

Metroid Prime-Nov 2002

Metroid Prime 2-Nov 2004

Metroid Prime 3-Aug 2007

DKC Returns-Nov 2010

DKC Tropical Freeze-Feb 2014

They had a rather consistent release schedule.

Back in the 6th gen they had a ton of projects that stalled and got canned; Thunder Rally, Retro Football, Raven Blade, an unnamed action adventure title. They pulled themselves together and did well from Prime 2 to Tropical Freeze, but since then we've seen them yet again fall into many years of not only having nothing to show for themselves but according to rumor also having projects go off the rails. Then there was the incident last year where a couple of ex-employees alleged that behind closed doors the studio had become a circus, with poor management preventing anything getting done.

They're just not a studio I have any confidence in.

Thanks for posting this.  It's so true.  I understand that their last 5 years don't have anything to show...but all being said they're allowed at least one mulligan.  Each of those titles is a 9.2-9.8 level game, with some people gibing Prime and Tropical Freeze 10s.  Not too shabby for a developer that has gone through all the changes they have.

Until we get firm confirmation that Retro's last 5 years have been for nought I will continue to consider them one of the finest developers making games today.  Their reattachment to a series they helped create (Metroid Prime) fills me with such joy.  More than anything I'm glad that Nintendo still feels they are to be trusted.  They truly know something we don't know, and I'm sure if their studio was imploding or bogged down in multiple failed projects that they wouldn't have put this series back in their hands.  I'm an optomist and I think this does mean that their previous project will soon see the light of day and will be worth the wait. 

I wonder how much did the other teams progressed in the scrapped version, and how much is Nintendo going to lose. That is, if this the case.

I don't think Retro is a large enough studio to finish a game the size of Metroid Prime 4 in three years like some people are speculating.  I'm expecting a four year dev cycle and for Nintendo to hold onto it for another couple of months so that it can be a launch title for Nintendo's successor to the Switch.

Who cares?

They should have done a Metroid-palette swap on BoTW. 8 mini worlds instead of one big world and that would have been 5-10m sales the bag.

Does anyone really want a Namco-Metroid , lol?

That's honestly a stretch at best. Those early 2000's projects you listed were all in the conceptual or early production phases, they were by no means games that were well into development or titles that had exhausted tons of resources. Many companies, including Nintendo, have cancelled projects at the conceptual or early stages of production, it doesn't mean a company is any less or more reliable as long as they aren't doing that for years. It's a pretty normal procedure in the gaming industry. 

So really, the point about their track record is pretty null and void. Being silent for a few years is not something which has been consistently replicated by Retro, so them being a studio which is consistently stuck in development hell isn't true. In fact, in order to even come to that conclusion, you first have to make the assumption that A ) They weren't working on multiple games and B ) that they weren't working on a singular project which, compared to their staff numbers and resources, was difficult to produce in the manner of only a few years. And all of this is also assuming they don't have a title coming out in the near future, for all we know they could be nearly done with their next game. 

So yeah, there's not really any evidence supporting this notion that Retro has a "track record" of development hell. They don't. 

That being said, being skeptical about Retro is understandable. Really, Retro having this game is no more or less reassuring to me than other studios creating the title. Because studios are more than just a brand name, they have a lot of baggage on top of that (like staff numbers, staff experience, resources, artistic direction, etc.). So i'm not particularly excited for Retro either, I'm just not negative towards it.