Deep questions from terrement
The first paragraph encapsulates my personal frustration with that kind of rule mechanism. I acknowledge that Evil Roy Slade probably wouldn't move at exactly the same pace all the time but the wild diversity given by rolling 2D6 (or any other variant) just turns the duel of wits between players into a 'game' of pure chance - I may as well pick a card from a random pack and that is how far Roy moves. The same argument applies to the use of just dice for shooting, melee or morale, everything becomes a chance result and for me this becomes boring pretty quickly. I absolutely acknowledge that for others it's what gaming is all about and that's fine as long as they don't dress it up as 'friction' or some other made up distinction.
In terms of running comparative games to judge a variety of rule sets within a given historical framework, life is too short
If you've been gaming for a while you pretty quickly realise whether a rule set suits your preferred style of play or not and you don't need to create a mental spreadsheet
If we take the recent process we went through, we played 2 games of Dead Mans Hand and, although it could certainly be seen as 'fun', it wasn't for us.
To close, I don't think I have ever claimed that my choice of rules is better than someone else's, I might think the rules I choose (or write) are a better representation of an historical time frame but of course that is just what I think, nothing more.