I've been away from SWTOR for some time, having grown bored of repeating the same content.
Now, I heard some good things about Onslaught, so I re-installed and re-subscribed.
The first parts of Onslaught are decent, even well-written story elements with missions that feel new and unique. Certainly better than the other add-ons. I actually found myself enjoying the game again.
Then I saw that the story includes a mandatory flashpoint. Flashpoints are great if you're a lazy writer. Just put loads of enemies that don't even threaten the player in their way, slow them down a bit. Then, just stick an OP droid in the middle of the level, who despite being virtually immune to the powers of the dark side, still needs half an army's worth of support. To top off the tedium, don't forget to add two powerful Jedi to the mix - no-one will see THAT coming!
Overall, I did enjoy the content, until the mandatory Flashpoint, which adds nothing to the game and is just an incredibly boring re-hash of the same old content.
I feel I've wasted my time, and my money. Good job, Bioware. :|