Definately get it calibrated/setup with a nice map and go from there would be my first shout.
Are you certain the cam timing and fueling is correct , my old engine was not optimum and once corrected made a huge difference in midrange throttle and generaly a much happier engine. They are known for not revving much as standard and this can be increased via the ecu of course. Evolution chips stg 3 + YBB is 7600 limiter for example iirc.
More modern ecu may also increase driveability but thats not to say the weber cant do it , A live map is the best way to go.