I know this is a very difficult to judge issue, but I need some opinions about this situation I have. We want to start a new project, a 3D isometric RPG, pretty much like Divinity Original Sin, with around 40 hours of gameplay, using Godot as game engine. Our current team is 3 people (2 modellers/animators, one programmer/game designer/writer) and we have a few more candidates. What I need to know is if a 8-12 people team would be enough to deal with such complex project in a reasonable amount of time, like 2-3 years. All similar games seems to be developed by hughe teams (Larian had 250 workers I think). Maybe Im aiming too high?

There are too many unknown variables.

1. Proficiency and skill of the people, which effects speed of the work done.
2. Free time of people during the week? assuming AAA studios budget at least 40 hours a person a week to run this calculation.
3. Design team break down of skill aka how much work can each person handle in a week?
4. Clarity of game design to the people?
5. time lost in administrative and organizational tasks if you don't have a producer?

That is just off the top of my head.

@GeneralJist Thanbks for bring to my attention some issues I havent considered, like 4 and 5. I thought about 3, but only in terms of myself. Considering that I found my limits when working in the previous project, I knew there was just some amount of code I could maintain at same time. But i blamed my age and thought that younger developers could do much more than me.