100's Vs 1000's

I have some issues with the Pelennor Fields battle, but goddamn is that scene where Theoden rallies his army fucking perfect. Goosebumps every time.

I guess it depends how it's shot, and what the actual moment calls for. It hasn't aged as well as I'd like, but LotR does it well enough by interspersing real actors and closer tangible moments with CGI and epic scale shots.

It really depends on the skill of the people making the movie. My problem with most CGI these days is that it looks like CGI. The movements of the CGI characters are always a little too smooth to be real.

10 CGIs

thats rather old, made by polish guys ... its top of the tops

Depends. You can't beat practical effects but LotR's combination of CGI and practical effects was superb, even if the CGI was noticeable. If done right, you can have 100 real-life actors, shoot them at different angles, and make it look like it's 10,000. And then splash some CGI because why not?

I will always prefer practical effects but CGI has its uses in the bigger picture (displaying massive armies, creatures, etc).

The Last Alliance battle of LoTR though...

You know, I wish they made a movie based on the Last Alliance

From your own videos in the OP, it is clear that real life actors are more powerful if the display of 'horrors of war' or the melancholy of defeat is the purpose. If chivalry, bravery, and magnificence is the aim, then CGI clearly has a more powerful effect.

Clever implementation of 100.

Depends on the movie and what it needs.

But let me remind you that on the set of Aliens, James Cameron only had SIX Alien suits. And there are only one (maybe two) scenes in which all of them appear on screen at the same time. Still freaking worked, and effectively gave the sense of the marines being faced against a MUCH larger horde.

So...I guess it just boils down to what the movie needs. If the movie REALLY needs thousands of people to be displayed at a single time, then that's what the movie needs and there's no way to get around that. But otherwise, I guess you just use what's in your means and use your skill as an artist to get the most effect out of it. That might mean taking hundreds of people and using good filmmaking to make it seem like more people, or it might mean using thousands of CGI characters. Just depends on what best services the movie.