But the point is we have models which predict quite specific values for the angular power spectrum, and when compared matches observations very well.
This is highly non-trivial. And for any new model to take over, it must do better.
It's not enough that it has potential to have some sinusoidal-like features. Lacking matching model predictions, you'd need to have a plausible explanation for why the features are missing from your model predictions. For example you used some first-order approximation for some term and due to <insert convincing argument here> a higher-order approximation should produce the missing features.