Well for the past couple years I've been playing D&D with a small group whose members fluctuate on such a regular basis that it is rather difficult to give a solid number of how many people generally play in it. Though including me there are 3 players who almost always play. Though I won't name any names I'll give a brief overview of our playing styles. For one you have the usual power gamer whose entire goal is to maximize his character's effectiveness in battle and anything involving skills. You have a player who is there entirely to actually have fun with the game and doesn't completely care about effectiveness as long as its fun. Then there's me, I could personally go an entire game without picking up the dice and be fine with it. I'm in it to tell a story, no matter how long it takes to finish the storyline I want to get there.
This group wouldn't normally be one that would game well together except that we all still have fun with it. Though the power gamer does occasionally make it difficult for me whenever I DM and I'm always the one DMing whenever he is playing since we only have 3 people and only two of which are willing/able to DM. And the other member of our group does occasionally veer off course when it comes to the storyline, but its still a fun group.
My point is that as long as your group is having fun then the game works, you can change the rules or even break them or your characters and the fact remains, D&D is about getting a group of friends together and having fun.