My 7300 is super sensitive to USB audio. I have to turn the USB Modulation Level down to about 10%. You might want to bring up the ALC meter on the rig and play with the level of audio until you see it just below the ALC zone, and then lower the TX power appropriately.
Internally wfview works at 48KHz. As the radio supports 48,24,16 and 8KHz, wfview includes a resampler which will convert this to the Internal rate. I will investigate whether it is possible to detect the current rate that the sound card is working on and use that as it may be preferable to resample to 44.1KHz in this situation?