I already messaged fizzer about this, but...

createGameAPI is fundamentally broken.

Either we
1) specify templateId
2) specify template settings

otherwise it looks weird. Current API let you specify both template and settings which looks weird because template itself includes all settings - and that includes players as well.

So logically:
1) IT SHOULD BE POSSIBLE TO SPECIFY SETTINGS WITHOUT TEMPLATE (since under settings tab I can override everything again)
2) there could be a separate call to generate/delete etc a template
3) maybe 2 calls for creating a game with template and creating a game without a template?
4) ... or allow template == null?

Unfortunately...
5) fizzer was a bit lazy to fix edge cases.

so here's my usecase. I have 4 friends and we play 2v2 at specified time once a week. So I made a template with them in UI, wanted to provide it in API and ... surprise! I need to specify player IDs again. Why?

Before you press the create game button when making a template with IU, edit the players then edit the template - save the changes. When creating a game next time (at least with UI), you won't need to enter the players again.

I could make a tool that creates a template based on the settings that you want the template to contain. PM me/reply if you want me to.