hearing this awesome soundtracks was one of the best things of Gwent beta but I don't get why it was removed after the revamp. because is getting really tiring to hear the same three pieces for each faction
It was mentioned [here] that there weren't any plans to bring the old OST back. A while later, it was mentioned [here] that a lot of requests were made to bring the OST back. That still doesn't explain the "why". That question is better asked in the ask a dev thread.
Also, a related suggestion to select different soundtracks.