When it comes to Season 8, there is no doubt whatsoever in my mind that the Goren and Eames episodes were in general better than those of Nichols and Wheeler's. Part of it is down to that Goren and Eames are and always have been far more interesting characters and their partnership gels a lot more, while Nichols despite Jeff Goldblum's game efforts never entirely clicked with me on first viewings (but he has grown on me overtime actually). Their cases were a lot better as well, evidenced already by liking the season opener very much and being very conflicted on the previous episode.
"Identity Crisis" is a fantastic episode, a Season 8 high-point and one of not many truly outstanding episodes of the latter seasons. Elevated in particular by the primary guest star, his chemistry with Goren and the ending. Season 8 was a pretty up and down season again (the case when two partnerships alternate and when primarily one is more interesting than the other), if not as much as Season 7, but it did have great and more episodes. Of which "Identity Crisis" is one of them.
Everything works brilliantly here in "Identity Crisis". It looks slick and has the right amount of muted grit, the photography doesn't try to do anything too fancy or gimmicky while not being claustrophobic and keeping things simple. The music doesn't overbear with the theme tune still memorable and the direction is accommodating yet tight enough.
Vincent D'Onofrio and Kathryn Erbe are as usual terrific, D'Onofrio in particular shining in the last ten minutes in classic Goren style. Love their chemistry in by far the best lead partnership of the show. Sam Tremmell is unsettling yet not overdone as a very psychologically interesting character. Loved his chemistry with D'Onofrio, which was very psychological and in a way that gave the chills but despite not being new type of character didn't come over as predictable. The rest of the performances are strong too, if not on the same level.
Script is thought-provoking and tightly structured throughout, especially in the climactic moments. The story is suspenseful and twisty, with no over-simplicity or convolution, and shines especially in the best scene of the show in a long time (one of the show's best interrogation scenes) where the tension was frightening, the intrigue was high and the acting was more than top notch. Trammell's character fascinates and is not over-simplified or ambigious.
In summary, brilliant. 10/10.