The amount of up/down bandwidth you have really doesn't matter as much as how much latency is on it. You can have a 50Mbit u/d connection with high latency that doesn't work as well for gaming as a DSL connection that is close to a NOC.
Not quite, you are over generalizing. Very often you have teams of friends that don't have great internet that play together but they are geographically very close to each other (I'm talking same city...not country)...being friends and all. When the game is setup it decides who is going to be the best host for the match. Since 4 of 8 in an Infinity slayer match have a good connection to each other its only natural for the game to chose one of them as host even though they have a subpar connection to the rest of the internet.
I agree that a good connection filter would be a good solution. There is a downside to this though, long wait times for a game and lower playlist populations...many people don't want to wait 10 mintues for a game with a decent connection...but it would be nice to give the option to those of us that do.
I think that the mixture of client-side hit detection and lag compensation is an all around good idea...I just think that the window of opportunity that the game allows is too long based on this games fast kill times. In the end the idea behind it is to make the game better for everyone playing..it just needs some tweaking.