Playlist Productions are nothing new. One improvement was that expensive sets no longer had to be built. In the past, shows might live on a ship for years. And at least you don't have to make reservations like some cruise lines. On the Excel ships they are no longer the primary entertainment, but an alternative. But to be fair, some Playlist shows are excellent - for example, Celestial Strings, and the main lounge is shared with variety entertainment.
As CC is at best a small percentage of cruisers, and complainers are much more vocal than satisfied cruisers, I wouldn't read too much into CCs influence on Carnival decisions.
Carnival knows they can't please everyone, but they do have something for everyone.