It wouldn't be fair to state "nothing changed" because a lot of things have changed for both better and worse.
Ilum was removed because of kill trading, which exploited the gear progression system, and because of the IMP vs REP ratio (which on some servers were almost 3:1). Also keep in mind that SWTOR is not a PvP first MMO, it is theme parked for story and PvE content. So if Open world PvP is your thing, then SWTOR would not be your first choice.
In light of all that, I think they nailed the Warzone PvP very well. Just hope they would finally start season one of Ranks because we have been in a very long pre-season!