I don’t think a “fan-first” classic upright needs more than a 5 amp motor to deep clean carpets. My Hoover Platinum Lightweight upright (Oreck clone) has a 5 amp motor and is excellent at deep carpet cleaning. Eureka’s Vibra-Groomer One brush roll has a nice helix design that provides more room in the brush chamber and helps move dirt into the fan chamber too.
Eureka’s top fill F&G bags also to keep the air path clear and free of obstructions, so airflow is maintained as the dust bag fills.