I respectfully disagree. The game is not easy to start, but very fair once you understand it. That's not to criticize your skill, but I think having fairness hidden behind experience is a good learning curve.
I think the strategy element you're missing is that your units also grow exponentially, if you plan them well. Getting four of the same unit combined unlocks insane powers, and boosting both power and toughness of a unit, especially shielded, gives exponential (geometric?) damage growth.
As a result, sacrificing your low-level units or high-level bad units to get re-rolls is totally worth it. Using the "freeze" ability to control your options is also key.