Your Cricket vs Baseball analogy is a bit more left field #pardonpun then what is being suggested here. Union/League hybrid.
RL & RU both come from the same apple tree that Webb Ellis created. the fields are the same. the balls pretty much same dimensions.
Yes, but they have diverged fairly dramatically, particularly in the past 20-30 years.
Scrums - no push v full contact technical scrums
10 metre offside at play the ball v zero metre rule at rucks and mauls
Different definitions of high tackles and sanctions on them
Different interpretation of what is and isn't a knock on
Left side/right side configuration v traditional inside/outside centre
League forwards have become far more aerobic compared to rugby conterparts
I like both games and watch Manly league and union play whenever possible. I go to league grand finals, super rugby matches and rugby tests. I prefer rugby, but certainly don't hate league. I don't see what can be gained from the exercise.