He turns 21 today.
In regards to serie A players younger than 21, he's got the best numbers for the last 30 years (probably even more, I didn't count it prior to 1985).
He's got 48 goals+assists on 58 matches. The closest to him is Alexandre Pato with 43 g+a on 77 matches before he turned 21. In comparison with some serie A legends, Del Piero had 24 g+a on 53 matches, Totti had 25 g+a on 88 matches, etc.
Staying clear from injuries, I don't think there is a risk of not making it big time for Berardi. He scores AND assists, unlike, say, Pato, who got his great number mostly from his goals. The only two attackers we had in the last 2 decades who both scored and assisted that much were Del Piero and Tevez.
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He scored or assisted on 17 of the 32 matches he took part in serie A this season. Tevez scored or assisted on 19 of the 32 matches he played in serie A the same season. That's more or less the same consistency.
Also, it's far from a guarantee that playing for a weaker team makes it easier to score and assist goals.