For the extra attack i would consider air superiority instead of flurry for pvp. Being able to knock the villains outta the air is very very handy, it also ensures (if their travel power is flight) that they stay grounded while fighting you and cant fly off 
I used to have jumping and SS as travel pools on Be-el, i changed to flight/SS with the last respec.. flight because i find air superiority invaluable and i then dont lose out on a power from choosing it, and SS because hasten is a godsend to the recharge times of dull pain and instant healing.
I chose soul drain pre 30 instead of dark consumption for pvp in sirens because it has a higher accuracy and a lower recharge time. I use this to help uncover stalkers when i've been placated. I have 3 Acc and 3 recharge on it.
If u havent already and can spare the slots put at least 2 Acc and also 3 Acc debuffs on touch of fear, i love fighting brutes that cant hit me 
Hmm leadership. Personally i wouldnt consider this for my scrapper as the benefits are minimal and i have less need than i do on my squishy toons to be able to spot stalkers sooner.
Whirlwind.. i considered this but ended up not taking it as i just couldnt fit it into my build, the only place i could have put it would have been instead of petrifying gaze, but i felt that was the one power i couldnt sacrifice for pvp, i enjoy being able to take part in all phases of hammidon raids when i attend Also the fact that it doesnt uncover stalkers it only knocks them back/interrupts AS.
Does any1 think its worth slotting tohit debuffs on the dark melee set?
I asked a the same question before respeccing, the debuffs iirc is 5% from the attacks which enhanced really doesnt give you a great investment for the slots. Chances are you will be taking down your targets one by one anyway so the debuff from touch of fear is really all you need, someone told me once it was either 30 or 40% debuff with 3 Acc debuff SO's, all i know really is that whatever i apply ToF to very rarely can hit me back.
lo peeps
I currently have a Dark/regen/dark scrapper. The last respec I did I scrapped body mastery to try dark instead and I quite enjoy it.
I now want to respec him again because when I'm in Sirens Call I have only a couple of attacks and my best mate - touch of fear. Its just as well I have touch of fear because of the downtime involved between hits.
I am really happy with my regen powerset as it appears to last well to the extent that assasins strike isn't that effective, unless there are 2 of them.
I currently have 2 powers in leaping and 3 powers in teleport. I am considering changing that to 3 powers in the speed power pool -
Flurry - for the extra low lvl attack
Super speed - which I plan to add at leasst one slot to so I can have an advantage when chasing/escaping
Whirlwind - I could e persuaded not to take this but I think it could be handy in PvP.
This will leave me with a couple of extra slots. Is i worth taking something out of the leadership pool?
Also, with the interServer rumbles going on I may look at going back to body mastery so I can get focussed accuracy. Do you think that its worth while?
Let me know what you think guys