The CLA250's turbocharged engine puts out a maximum of 208 horsepower, which is fine. Really, it's not bad.
But one doesn't ordinarily buy a Mercedes-Benz to get "fine" and "not bad." When I'm driving a Mercedes-Benz, I expect "Wow, that's excessive." A push on the gas pedal in the CLA250 feels postively polite, especially when approaching a hill or trying to get around traffic.
There is a cure for this problem and it's spelled with three letters... AMG. That's Mercedes' performance division and they stand ready with the AMG CLA45, the impolite version of the CLA.