I think there's a bit of a disconnect between the criteria for best developer and the relation to GOTY. Being a great developer doesn't necessarily mean that you're making the next GOTY. Being a good developer means making quality titles, making regular efforts to listen to the community to improve the final product, and having consumer friendly DLC practices in an age where DLC of some kind is a given with every big budget title.

It just so happens that CD Projekt Red made an incredible game, and then went on to be an example for basically every other developer by providing free DLC, expansive, inexpensive paid DLC, and listening to the community to provide patches to the base content that offered improvements in all the right places.

This is one year where best developer and GOTY happened to walk hand in hand, but just because CD Projekt Red was a super consumer friendly developer this year doesn't mean that another game couldn't have won GOTY. We all knew that The Witcher 3 was an incredibly strong contender though, and it was basically guaranteed as GOTY unless something could manage to dethrone it. Ultimately though, nothing did throughout the year on a critical level, and thus, the best developer of the year also happened to produce the best game of the year.

Edit: @OP - You seem to think that best developer requires game volume, which I see as odd. Why should a developer have to divide their resources and risk lesser products for the sake of praise at an award show? Should every director have to direct multiple movies a year to be best director? Every musical artist have to put out multiple albums in a year to be the best artist? That is just dumb criteria that values quantity over quality.

I don't dissagree with that sentiment. I just find the idea of the seperate Developer of the Year award to be too close in criteria to the Game of the Year, especially when those developers are the developers of the Game of the Year nominees. They're basically getting nominated for the exact same thing twice.

It shouldn't be Developer of the year but actually Game Director of the year. Because you can be a great Director/Designer without creating the GOTY due to budget constraints.

Actually games should have the same categories as movies with sound design, art, writing, directing etc.

Going further, can you consider "Nintendo" a developer? They are a publisher. They have several development teams. It's not like any single of those development teams have released more than one game this year.

To me it seems unfair to compare the combined software output of several inhouse development teams a publisher owns, to the output of single teams from other publishers.