True, referring URL stats are still very important. That is something I would like to see implemented at every affiliate program in the future. It hasn’t been forgotten. 
The purpose of this list (and the other one) is to help us see what we have in front of us now, at this point in the game. There are many characteristics that can be used to evaluate an affiliate program. Examples:
– negative carryover
– bundling
– minimum payout
– stats quality/accuracy
– conversion ratio
– responsiveness
– player treatment
– etc.
Some of these qualities are subjective, and can vary from affiliate to affiliate. The first three items in the above list are measurable, “black and white” characteristics. Organizing the affiliate programs by these traits is useful to a point, but of course many other things need to be considered, such as the conversion ratio, how well the players are treated, etc.
Certainly, negative carryover and bundling aren’t the only things to consider when deciding which affiliate program to promote.