From what I know for now, They want to create these "dedicated servers" just so that there is no loss of progress. A lot of people (especially veterans) have lost their original progression many times. Fault is on the wrong configurated of the Steam Cloud by Devs.
I think we will still be able to modify progress, even Cheat Engine or another tool. Hacked points/items will be available in our game until we restart it.
Just do not believe that they will completely rebuild this system, this game was made on P2P with local save. It will cost them a lot of money and time to change it. And the DBD population is constantly falling. Does that make sense? I doubt it.