The fact that something "can be learned through experience" does not mean that it is a good mechanic.
But it does mean it requires skill. Caldwell is a card where you'll need to think about how and when to play him (unless you sacrifice him with Mo or NR). WHR uses the dominance principle and once you've learned that you can apply it to all cards with the same ability. Whether or not WHR is too strong compared to others is besides the point. As for Caldwell's RNG, it's easier to look at Curse of Corruption. It states: destroy the highest unit. When two units have the same strength, what do you think will happen? This makes you think about the game.