You have a lot to change, the Bryston DAC is a good dac but not in the league of setting up a super system.
Moving to a better amplifier will help, it comes down to price vs performance. The NEMO's are incredible amplifiers for the big B&W they were designed to power them.
Also Chord's amplifiers are also amazing with the B&W.
I would also look at power conditioning, are you using any? Power Cables? Vibration Isolation, room tuning?
All of these items play a crucial role of making a system come alive.