Indoor and outdoor are very VERY different.
Indoor you will find lots of people who just want to run around and do magazine dumps at anything that moves.
Outdoor you get some of that, but you get more of the tactics, and flanking. Overwhelming fire is not so much a factor. One good person can take out a whole squad, or secure a whole village (it's fun when you are that one person...
).
Now, indoor is awesome when it's scenario play like the BSP Challenge or CQC1-7, but those events have come and gone, and there are none even close to being on the horizon right now...