"Empire's" story did sound very interesting, especially concerning the motivations of the star prosecution witness. Other than that and my general love for 'Law and Order', a big interest point was seeing how Julia Roberts would fare in a role that was quite different for her at this stage of her career (where she was best known for her romantic comedy roles). And it is still not the sort of role that she visits an awful lot.
Although there are episodes of Season 9 that are a lot better, "Empire" is compelling and very high quality. Not everything works, including one regular character not being written particularly well here and one part of the story that could easily have been written out. But when "Empire" does work, it does so wonderfully. While not a must watch, this is an episode that is well worth seeing (which is true with a lot of the show's run).
Shall start with what doesn't quite come off. While the story of Ludlow and Curtis was interesting, this is another episode where Curtis comes over as over-stubborn and somewhat petulant. It is agreed that his anger on the stand is not particularly buyable which felt forced and too mild, he does come over more as easily irritated.
Do agree too regarding the coda, that was completely pointless and tacked on as well as (uncharacteristically for the show) self-indulgently written. The first quarter or so is on the routine side, it is once Ludlow comes on the scene showing her true colours and the legal portion where "Empire" comes to life.
Coming on now to the many things that are done well, the acting is very good with the slight exception of at times Benjamin Bratt (not enough fire when angry for instance). Sam Waterston is authoritative and ruthless and Jerry Orbach's one-liner delivery always delights. Daniel Hugh Kelly does strong work in a type of role he always played very well and it is great seeing Edward Hermann again. Roberts comes off most memorably, she has a real slippery eel of a character that she plays quite unsettlingly.
Furthermore, "Empire" is a slickly made episode, the editing especially having come on quite a bit from when the show first started (never was it a problem but it got more fluid with each episode up to this stage). The music is sparingly used and never seemed melodramatic, the theme tune easy to remember as usual. The direction is sympathetic enough without being too low key. The episode also has a thoughtful script that like a lot of 'Law and Order' episodes raises interesting questions worthy of debate with somebody. The story is tactful but also pulls no punches, making one feel sad and angry. Nothing is too simple or too complicated and the second half even is riveting. The character writing and interaction are near-on point.
Summing up, good but not great. 7/10.