Mind you, they made some changes that the game actually needed from the get-go. Their profession structure was blurry and vague, so much so that no profession had an idea of what its niche was. However, I'm not talking about changes, I'm talking about method.
What SWG discovered, in their polls, was that many people bought the game to play a Jedi, but that Jedi was not a default choice, so they left the game. Those joining the game also found that it was difficult to learn, so they left the game. That's the origins of the radical redesign. The company made a decision that they could afford to loose the old players, as the potential player inflow from the new design should displace those losses.
On top of that massive change, Sony hid the change until a month before the combat system was implemented. They then deployed the new combat system with too many bugs. Both these actions disenfranchised the existing community.
All this makes me sad. I did enjoy the game, and I do have a soft spot for it. Now, the game that I knew is pretty much gone.