@343: "A competitive game can be played casually but a casual game can never be played competitively."
I would disagree, here's some examples...
1. Golf: Casual play is with handicaps and differing tee off points as well as rule sets where competitive play is a focused no handicap specific tee off that still differs between genders.
2. Formula 1: Highly competitive that even has mechanics of financial limits, technical design limitations that are all designed to balance a car/team so the driver is the most important competitive factor. Can this be played casually? Directly the answer is no it cannot, however, a watered down go kart version can be played by casuals. Again very differing rule sets and vehicles between casual vs. competitive.
3. Soccer: Everything set in stone for competitive play but casuals often play soccer without the exacting field, team or structured requirements. The direct competitive version can be played casually but this is usually in club organised teams/venues where the more popular global casual version of backyard soccer cannot be played competitively.
As you can see with a few simple examples competitive and casual are rarely exactly the same and even when they are the casuals tend to bend the rules or assets for more flexible play.
How does this translate to Halo? Competitive play tries to iron out the random, promote teamwork and practised regular teams with generally smaller and asymmetrical maps. Does that atypical competitive play mean casuals can play it? Yes it does.
However does the real world data from casual play show that casuals want to play the competitive Halo settings? The answer is a resounding NO. Casuals while they may play competitive settings they often don't have a regular practised team, nor do they want to play against those regular competitive in their settings.
Some casuals just want to drive warthogs, some want to try and get flag beat downs on the back of mongoose, some want to play flood etc etc.
So while your statement is true in theory it is far from the reality of casual vs. competitive play. To return to the example casual have far more fun with their average go kart vehicles and basic track than going to full CAMS3 licensed $10K go karts on a custom league track and tournament event.
You get the idea.
Edit-
I also get very tired of how competitive everyone wants Halo but in reality online play for matchmaking and rank has less to do with settings and mechanics where latency and host are factored in. I still find it sad that competitive is touted so much but you guys'n'girls here at neoGAF hardly ever talk about Good Connection Filter. To me a far more important issue over the actual competitive settings.
Sure I agree a playlist for default Halo and a playlist for MLG should have your competitive settings. Sure I agree the custom games should have allowed more customisation for such game mechanics too. However I draw the line that the whole game should be competitive based just because casuals "CAN" play the competitive settings. Each should have their own settings and playlists, your statement does not factor the casual modes without competitive at all and that I have issue with.