I haven't really touched disco in a few months but I was around when a lot of these new changes were being implemented. Discovery's pvp and combat system in general was always about "Easy to learn, hard to master" and that has always been essentially the core of the game.
The new changes to shields, mass, and powercore all lead into, as others have said, just not a fun experience. Personally I can understand some of the changes made, but most simply just make the game needlessly complex and overall less enjoyable. With all these changes to the core aspects of the game, it is now less of an "Easy to learn" and now more of a "Hard to learn, "Harder to master" game. The more we change and add the more complex it will be for new and returning players to enjoy.