IP monitoring is awful, how do you tell the difference between a single player with more than 1 account and multiple players on one account each connected to a router?

You don't. You just blast 'em all and let God sort them out.

Yeah, no thanks

I agree. Also, people might have multiple PCs and in different places.

Moreover, IP locking will not work for technical reasons too: proxies, spoofing, some people have a dynamic IP, etc. For example, my service provider assigns me a new IP every day.

Neither an IP address nor a computer is a person, and they can't truly be tied to a person.

I agree with Brother Kane. Planetside 2 was diminished by the lack of Faction Locking.

Faction locking would instill actual Faction loyalty and pride in your Factions acheivments.

Only issue I could see is population balance, but there are other mechanics is address that.

Trust me when I say, faction locking will piss off alot of players, for a few things.
One being the fact that you paid for all four factions, so you will want to play all four
Two, new players will want to try different factions to see what they are like, so they can understand the game lore wise and the general fun of it.
Three, there isnt anything that can go wrong if this game doesnt have faction lock, whatever faction has a large amount of players will get harassed by Tyranids as the counter balance.
Four. If there is faction lock and 40% of players are playing space marines, then guess what? Every other faction will have to deal with that and it will be very frustrating.
Five, with future content such as new factions coming out, you cant play them because of the faction lock.

Unless it is something like a timer lock on a faction, so you cant swap for a certain amount of time, say max a week, then there will be no point in locking factions, unless you want to anger people who buy the game specifically to play multiple factions. There are people that will want to stick to one faction, so let them, dont lock people who dont want to to a faction because of balance, just let those faction fighters do that.

It is clear that you just don't understand what is being discussed. None of your reasons are founded on any evidence or proven fact, a lot of it is loose conjecture and opinion. Leave this to the big boys.

Clearly cupcake you have never played Planetside 2.

Ignorance and lack of knowledge makes that perfectly clear to the rest of us.

total faction lock would undoubtably be the stupidest idea ever,

temporary faction locks would be bearable within limits, but again I would point out that any FL that lasted much more then an hour would severly impact negatively upon the casual/weekend/short time window gamer,