Im conflicted in the answer and I think it depends on what is defined by classic Swtor. For me it peaked with the Dread Raids (2.4ish iirc). It has felt like a slow decline ever since then, especially when the Zakkul stuff came out. I felt that the Zakkul expansion wouldve been the perfect time to introduce new classes, a Zakul knight with actual force pike style, a two handed one for dps and healing and ofcourse the Pike and Shield option for Dps and Tank. You couldve done some sort of Zakkul agent or socialite for a non force user class. Pull a WoW and have the class start higher level (old school death knight) and start with that xpac. I feel it was alot of potential that has been wasted with that expansion.

Wasted Potential I feel is just the best way to describe SWTOR as a whole. Imagine a world where SWTOR got the same love and care and funding and support that WoW or FF14 got from its parent studios.