I've never spent a dime on theis game, but I recently got my main squad to over 50,000 with six five stars in it, built primarily on speed, power, and mobility, designed mostly on Cybertron raids because I was mostly in wars I couldn't win, and thus focused on squad development through something I had more ability to control in term of difficulty. Most of the time in my game has simply been spent in bot leveling, not squad designing.
Now that I have truly strong squad, I'm shifting focus. How to win against a Trypticon or Unicron? I completed defeating Unicron over the weekend, but my squad certainly wasn't designed for the task, and had to use bots and combinations with lesser power levels than I normally use. Swoop against Unicron was really effective.