Most of them are based on personal prefference.
Imp Evis over Murder - I've given up trying to raid on my rogue. Nobody's gonna let me raid as daggers, and I love the subtlety tree too much. I've never been totally sure if murder works in PvP, though I've assumed it to. The reason there's 1 point in imp evis is basically because I used to have 3 and took 2 out to place them in imp expose armor, which I felt was going to be a very nifty trinket. My new WOTLK build takes the point from the assassination tree and puts it somewhere in the subt tree... At the moment it's more of a leftover point with no real alternatives to put it in.
As for Cheat Death; I used to have it, until the nerf. I thought 210 resilience would be good enough to make it worthwhile, but apperantly it isn't... Whenever Cheat Death procced I died anyway 1 second later. In the situation I was in, removing Cheat Death from my spec meant I could pick up the second point in Dirty Tricks and Elusiveness, two talents I had never really bothered with but had always had an eye on.
Why no Deadliness? I ran out of points. Not having Deadliness is more or less my sole real regret... The thing is that I just can't afford to drop 5 points to pick it up. Most of the talents I currently have in my spec have become so 'grown' to me I couldn't live without them anymore. And everything I woúld be willing to drop (like Sinister Calling) is simply better than Deadliness.
Heightened Senses over Master of Subtlety - I got really sick of rogues ALWAYS having the opener on me rendering my 5/5 master of deception useless. I got so fed up with it I planned to get whatever +stealth and +detection I could get my hands on; once I get a worthy cloak (come WOTLK, I only do some casual PvP on my rogue as of now) I intend to get a +stealth enchant as well. I used to have Master of Subtlety and decided the points were simply better off elsewere; it's a temporary bonus which isn't all that good and to me not worth 3 points.
Posting my WOTLK spec might shed some more light on (specifically) the last situation. I intend to start serious PvP at 80 with my pall who'se also a rogue. I would be specced like
this, opening first with a cheap shot (or even ambush, depending on the situation), hammering on an improved 5 point expose armor and (though combopointless) attempting to get up a kidney shot. My pall would spec
this, opening with an ambush after me and then entering shadowdance and ambushnuke the target. (Note; since I hope to be the one focussed his points from Wrongfully Accused go to Waylay).
And forgive my noobiness, but what's a WWS?
Edited, Aug 10th 2008 12:26am by Mozared (Trying to turn the post into something readable) Edited, Aug 10th 2008 12:28am by Mozared