Counterpoint:
I know grammatically it isn't the most correct, but I don't see anything non-idiomatic about "amount of features".
Reason: "Just the right amount" is a set, idiomatic expression. "Just the right amount of ___" is just extending the expression. IMO extending idiomatic expressions exempts it from a lot of the formal word-pairing conventions in English.
But I'm no linguist.