Well, wasn't agent Dark also supposed to be a highly trained agent?
And yet it was there, also this VR training area thingy.
Maybe I'm not that good at fps in general, but I for example have problems getting used to TF2 - and it's something I'd appreciate in there, because if you're always getting killed almost instantly, you don't have much time to learn about your weapons.
And it seems, there are players who get the exact same experience in GE: S.
You're absolutely right about that HL2 example, that's also why it came to my mind in the first place. But HL2 can take its time to introduce weapons and mechanics one after another due to being a SP game.
And that's my point - it's not only about shooting movable or immovable targets but also getting to know features like exploding your remote mines in mid-air, getting to know which weapons can penetrate, timing exploding stuff or stacking rolling explosions to your advantage.
I know, this stuff IS well documented (->wiki) and you COULD test it yourself locally if you wanted to, but honestly.... few new players do that. There are many who join a server, play for a few hours and then eventually discover there's an aim mode they could use - or ragequit before.
Well, I'm repeating myself there - I guess our opinions concerning fitting in are clearly stated.
Let's see whether it's given a shot or not.