While TrainerRoad's plans certainly have value for speed training, focusing solely on power output might be shortchanging yourself. Sure, power is crucial, but so is handling. It's like having a beastly engine in a car with wobbly wheels - you're not maximizing your potential.
That being said, it's a bit of a leap to say that those who stick to TR plans are automatically at a disadvantage. There's no one-size-fits-all approach in cycling. However, it wouldn't hurt to spend some time honing your bike handling skills. After all, what use is raw power if you can't stay upright when the road gets twisty?
So, while TR's plans are worth considering, don't forget about the importance of balance and control. You might find that a well-rounded approach serves you better in the long run.