Val Kilmer.....

A great performance doesn't mean necessarily a "powerful" or "energetic" performance. Of course, it's easier to clap our hands for Vincent D'Onofrio's or Peter Sarsgaard's performances, rather than Val Kilmer's, but that's because Poo Bear or Jimmy the Fiin as characters, have much more color than Danny/Tom.
I know that some people may see very little changes in his "two roles" (I'm referring to who he was before and after his wife's murder), but, like Flyo said: "he's a quiet man". Which makes totally sense to me, considering he's a trumpet JAZZ MUSIC player. Have you ever met a jazz player? They're people loving profoundly a nearly dead art. They are rather quiet people. Then, after the murder, Tom becomes Danny and hides his anger behind a wall of meth: that's why he always looks so calm.
Think about Jared Leto in "Requiem for a Dream", the taxi sequence. After he saw his mother high as a kite, he can't help but crying his eyes out. He takes a quick fix in the cab and, boom, he's completely apathetic. Danny Parker is high all the time. The character is supposed to look like a man who's hiding his pain in this new man he created....until you find out that it was all part of a plan (which I love).
I don't know. Perhaps I'm partial 'cause I LOVE this movie and I personally appreciate some of Kilmer's performances ("The Doors", "Tombstone", "Wonderland" mostly), but I really think that another actor wouldn't have had the same "physique-du-role" (not anymore, since Kilmer is obese now).

Cheers

FMP

He's always a bit cold and emotionless in most of his roles. Which can make him a hard leading man to relate to. He needs a good foil. See: Kill Me Again, where he has two charismatic co-stars to back him up perfectly. Then, Heat, of course, where he totally works because all the other villains -- and the hero -- are a bit more lively.

He's a great actor but yeah, I can see why his style and mannerisms are hard to relate to.,


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Shuji Terayama forever.