I don't think that it will be like an Adder. More closer in my belief is that it will be to the Viper what the Viper is to the Eagle: Worse than the Viper in manueverability, higher costs across the board, but more firepower, slightly more speed, and slightly better protection.
I'm pretty sure that it will be a strongly combat-leaning ship, unlike the Adder or the Python. It will probably have little internal space, and might have power plant issues if fitting shield cells.
Just my guesses and predictions.