5.0 for sure with the entire Ascian backstory
5.1 and 5.2 were forgettable honestly.
5.3 that took Elidibus from some meme comic villain to a tragic backstory with real motivations that anyone could sympathize.
5.4 I never liked Gabu so that should tell you how I feel about a patch devoted to him 85% of the time but the trailer is 99% devoted to MUCHHHHHHHHHHHHHHHHH more interesting content.