Let's examine some of your observations.
Limit Strength Vs Power
The Deadlift, when performing near max loads, is a Limit Strength Exercise.
Swing are a Power Exercise.
Strength Is The Foundation of Power
Novice and Intermediate Lifter initially increase Power by increasing Limit Strength; to a degree the greater your Limit Strength, the greater your Power Output is.
"Lifting Heavy Weights Make You Slow"
There is some validity this statement that I have addressed in previous post.
Individual who solely train with Heavy Load will experience a decrease in Power and Speed.
That due to the conversion of the "Super" Fast Type IIb/x Muscle Fiber to Fast Twitch Type IIa Muscle Fiber.
"Super" Fast Type IIb/x are developed and utilized more in Power and Speed; Type IIa Muscle Fiber are employed more in Limit Strength.
Misreading The Tea Leaves
Both the Deadlift and Swings can be utilized for condition. dependent on how the program is written and performed.
Secondly, Judo is a Power Sport. I spent two years in Judo.
This takes us back to "Limit Strength is The Foundation of Power".
However, solely performing Limit Strength eventually will decrease your Power and Speed; one research article that I posted a few days ago went into that.
The key to ensuring Power Development while increasing Limit Strength is...
Conjugate Training
Olympic Lifter are the "Poster Children" for Conjugate Training. They posses enormous Limit Strength and Power due to that fact that they train both at the same time.
Research has demonstrated a Synergistic Effect occur when you train both; Power increases as does Limit Strength.
The Deadlift Is A Limit Strength Exercise.
That means it's going to develop more Limit Strength than a Kettlebell Swing, a Power Movement.
The Right Tool For The Right Job
Olympic Lifts/Movements and Kettlebell Swing are Power Movements.
Research has demonstrated that that up to 52.6 w/kg Men of Power Output are produced during an Olympic Movement.
Are Heavy Kettlebell Swings Better Than Deadlifts? | T Nation
Dr Bret Contreras research on Kettlebell Swing demonstrates they rival the Power Output of Olympic Movements
The Deadlift, when preformed with a moderate load for Power Training, produce up to 12 w/kg of Power.
Thus, over 4 Times the amount of Power is displayed with Olympic Movements and Kettlebell Swing compared to "Power Deadlift Training".
Take Home Message
1) Use the right tool for the right job:
a) Power: Olympic Movements and/or Heavy Kettlebell Swings (Trap Bar Jump Squat work as well. Another topic).
b) Limit Strength: Heavy Deadlift (Traditional Exercises).
c) Conjugate Training: It provides a Synergistic Effect. Power enhances Limit Strength; Limit Strength enhance Power, 2 + 2 = 5!
Kenny Croxdale