Yeah, "togetherness" [among the idols] is the theme of the anime, not the producer. He's merely a catalyst. I don't think the anime is supposed to be a direct adaptation of the game, or else it'd be more like a harem series, where everyone flocks around Producer-san and can't make any decisions on their own without him.
I think viewers would get a little tired of it. In the game, /you/ are the producer, so you get all the attention. So the only way that would work out is if every episode were like episode 1, from a first-person perspective. That'd be the most like the game. Instead they made P-san out to be his own character, which I find a bit more realistic in an anime setting. He does his job, helping them realize their potential in early episodes, but towards the end of the series, they've grown up and become more talented and have started taking care of their own careers. I couldn't be more proud of them all.
In the games, you focus on one girl (or three), and the rest of them pretty much don't ever appear. That wouldn't work out too well in the anime, unless you divided the series into separate arcs like visual novel adaptations. We wouldn't get to have so many episodes with all of them as a group together, and the tension would be a bit weird if P-san has to change his focus from one girl to the next so suddenly. (No jealousy amongst the others?)
I view the anime as a separate entity. It's titled IDOLM@STER, despite being loosely based off the second game. Jupiter and RK weren't really pitched as rivals you needed to defeat, and they added in Shinkan Shoujo (whom I'd like to see more of), Kotori goodness, and lots of performances. Too many awesome things have occurred for me to be disappointed now, and I have felt that way since episode 10, I think.
