How, exactly, is that a worse idea than needing to buy a separate addon in order to be able to play with more than 1 or 2 people? I'd say that multitap-free multiplayer is a very good thing... having to buy an addon in order to play some multiplayer modes is annoying, and the 3DO had a pretty interesting idea there. Microsoft used it later on, the original Sidewinder Gamepad for the PC had a gamepad port on it, so you could plug a second pad or joystick into the Sidewinder and switch between them (for certain joystick models such as the Microsoft Sidewinder 3D Pro). Great idea, I thought.
Agreed here as well for sure, N64 games did not suffer in any way graphically or in game design because of the cart decision. The only things that were really affected were music and making it harder for developers not good at compression, really (the low-res textures are mostly because of the tiny texture cache, not the carts).
3d N64 game complexity and depth was above that of your average game on any other system that generation, and at the top end they did more than anything possible on any other system that generation.
Hah, now that I agree with. Quite true.
FMV doesn't just mean live-action video, it also means CG cutscenes. And if one thing hurt the N64, it was the fact that JRPG developers couldn't do their precious pre-rendered FMV cutscenes on N64, so they all went to PSX instead, and doomed Nintendo in Japan that generation.
There were some other factors, but I think that was one of the biggest ones. Of course Resident Evil 2 for instance shows that you CAN actually do FMV on the N64, but it takes a lot of effort...
Using cartridges on the N64 was absolutely not a mistake, it was a good decision that made games on the system more fun and less frustrating (no/less load times, etc).