An interesting thread. I would imagion the developers would have access to the global stats. They would be able to tell us the descriptive statistics with regards to the KD ratio's of players. You would need more than Excel to analyize that amount of data though - kind of puts the analysis out of most peoples reach.
The global KD (all kills: all deaths) ratio would have be nominally less than 1. I don't think the amount of suicides would materailly effect this.
There is a whole bunch of BS that would make the results of little to no worth. I don't know if anyone has ever looked at the leaderboards - the first 20 plus pages (thats as far as I got - I am at work LOL) have people that have impossible stats. They are likely boosters or cheaters. I imagion there are similar problems with the other end of the data.
You would have write off a lot of bad data to get a good picture of a 'normal' player. From my glance at the leader boards there is a lot of garbage in there.
One thing I would like to be able to see is an analysis of time played vs KD, KD vs SPM etc...
Everyone is able to level up his average, but not everyone is suited to walking alone and killing multiple enemies without dying. If you are not good in doing this you have to play with teammates. Teammates that work together are almost always likely to win a match, even if their ratio's suck.
The Community average will be more around 1.25 , I see alot of players with KD's of 1.00 but gun KD's that far excell the KD written on the Combat Record.