Not a replacement, Retro is just a veteran studio, a very good one, Rare was a whole game company, with multiple studios working in it, also now Rare sucks because before and after it was bought by microsoft many of their key developers left going to Free Radical, Silicon Knights, Nintendo, Zoonami, Retro, and others...

I think some of these opinions are a bit misguided and you may want to look a little deeper than the surface.

1. Yes Rare did more, but what's the companies staff size. Could Rare be bigger than Retro? You may have a point, but without this detail your statement is unfair.

2. Retro didn't bail. They were iron handedly told to forced to make sure MP was of the highest quality. That was the nice term. The reality Nintendo told them to only make this game so it could get all the attention. Not fare to pass this judgement on Retro.

3.This is really just number 1 in difference words

4. heh, here you have a point.

The main difference, aside from the difference in development demands, is that Rare was their own company, nominally independent though 49% Nintendo controlled, whereas Retro is a full Nintendo subsidiary. 

just like he said

but I think the fact that retro doesnt release to many titles is bcuz Nintendo decides on what retro is gonna work.Retro may be a great company but I dont think Ninty let them be free like Rare used to.

I am sure that DKCR, is not the only thing that Retro is working on. I fully expect something new from both them and Sora team at the next E3.

Its possible ...

While I don’t know what Nintendo’s strategy is, if I was trying to turn a single high quality development team into two high quality development teams I would probably split the team, hire as many experienced developers as the teams could handle, and have them each work on a project that was relatively small in scope. After that project is completed, you continue to increase the scope of the following projects and add the necessary developers until your two teams are the desired size and quality.

The reason for an approach like this is that it takes time for a team to gel, you have to hire slowly and grow over time because (in all industries) there is a limited number of quality people looking for work at any given time, and you want to be careful not to give your team more than they can handle.

If we are comparing RARE from the mid 90's verses Retro we have a competition.  Using the current RARE studio vs. Retro.... well, there is no way RARE wins.

If anyone knows how to keep quality high during expansion it is Nintendo. I see Retro as the company that creates Next Generations defining game.

I loved many of Rares games. I love Retros games. I do not want them be Rare I want them to be Retro

One thing I'll say about Rare:  They can make a damn good looking game.  When DKC came out, people were calling it the best looking game, ever.  When Killer Instinct came out, people were calling it the best looking game, ever.  When Starfox Adventures came out, people were calling it the best looking game, ever.  People still call Conker Live and Uncut the best looking Xbox game, ever.  And, when Banjo & Kazooie:  Nuts and Bolts came out, people (not many people but a few--on this very site, no less) were calling it the best looking game.

Retro had the same effect with Metroid Prime but since then, they've been hampered by hardware limitations.  I'd love to see what Retro can do with some truly powerful hardware and I'd love to see what Rare can do if they reallly cut loose with the 360.