Which is more like Xenoblade X :   Mass Effect, Dragon Age, Dragon Quest, Tales, Final Fantasy or any game made by Nintendo?  The closet game currently in production, I would say, would be Final Fantasy XV.  Monolith's games are like nothing else offered by Nintendo.

^^^

If I had to choose though, I guess monolith soft.

This is tricky.

For me, the Metroid Prime Trilogy is better than the Xenoblade games, however, the last of those games released almost 9 years ago. If we're talking about recent output, then Monolith has surpassed them in my mind, simply because I much prefer Xenoblade to Donkey Kong. Also, it's worth noting that Monolith helped develop Skyward Sword, as well as many other huge Nintendo games recently. I know that Retro has helped with Mario Kart, but it's not quite the same.

Basically, as long as Retro is making Donkey Kong games and Monolith is making Xenoblade games, Monolith will have the upper hand in my book. But overall, Retro has made the superior games, albeit 10+ years ago...

Couple things.

Firstly, up until a recent hiring spree in mid-2014, Retro was roughly half the size of Monolith Soft; a comparison between the two in terms of total output is entirely unfair. They're still 25% smaller and are still restricted to one development studio, whereas Monolith has two (one in Tokyo and one in Kyoto).

Secondly, very minor note, but if you're including re-releases in your comparison, Retro also developed DKCR 3D.

Then, let's split into 2.

Monolith still developed 4.5 games, more than those 3 that Retro did, with one of them being Xenoblade X and a port of a massive game like Xenoblade. Retro does not have anything to win this comparision.

Keep in mind that the "co-developments" mentioned require significantly less people than does developing an entire game. Monolith has the people to develop a game on its own (like X), and assist with several other Nintendo projects. Retro did (and likely still does) not.

To put this into example form, imagine you have a studio with roughly 120 people (i.e Monolith's size) and 60 or so people (Retro's size pre 2014). Let's say, for the sake of argument (I'm sure it would differ from game to game), that you need 55 people to develop a game, and 5 people to assist with the development of a game already in progress. Retro, in this case, can develop one game and assist with one game. Monolith, meanwhile, can develop one game, and assist with 15. If you equate the effort required for assisting with a game to the effort required in order to make a game from scratch, the results will be extremely skewed towards the larger company.

Then keep moving the goal post: 1 game vs 1 game. DKCTF vs Xenoblade X. And here there's no excuse. Retro was capable of develop Metroid Prime and Metroid Prime 2 in a single gen, Metroid Prime 3, MP Trilogy and DKCR on the Wii. They can do a lot better than a simple 2D DK game.

I played Dragon Age when it was given for free by EA, and I found it terrible... Absolutely nothing like Xenoblade.  Xenoblade is a RPG, a genre where Nintendo was lacking, and a JRPG, but there are currently no games like it on the market. Western RPG's are totally different and the other JRPGs have taken the bad road.

I did not know Retro was so small, I thought they were around the same size than Monolith before Monolith opened a new studio. 50-60 people is very small to do HD games, that's maybe why they choose to make a 2D game.

Anyway we shouldn't juge the co-developpement, only the gaames they made completely because we don't know what exactly they did or didn't. Skyward Sword for exemple was the work of EAD, so was Mario Kart 7.

Well, when the comparison is set up in such a way that you might as well be asking why Austria isn't as profitable as the United States, then yeah, the goalposts do have to be moved a bit.

Anyway, I really don't get why a 2D Donkey Kong game is considered so widely to be a failure. Certainly not a wildly ambitious project, but great games don't need to be consistently pushing the limits of the software. Nintendo wanted Retro to make another DK or Metroid game, and they decided they'd rather try and perfect DK than go back to Metroid. They've since been assigned to something for the NX, and chances are we'll hear about it either at this year's E3.

More than anything, though, the complaints leveled at Retro are that they haven't been as productive this generation as they have been in the past. And from that standpoint, let's look at productivity levels. Over the Gamecube's lifetime of 5 years, they developed 2 games (Prime and Echoes, with Prime receiving significant help from Nintendo). Over the Wii's lifetime of 6 years, they developed 2 games (Corruption and DKCR) and re-released MPT. Now, over the course of the Wii U's lifetime of only 3 years, they've ported DKCR to the 3DS and made Tropical Freeze. This is basically par for the course for Retro.