Where is the evidence that Bioware removed it for balance reasons in the first place? I've never seen that.
The only thing I have seen is evidence that if put back in, it wouldn't affect balance at all, as Double Strike would still be an inferior option to anything else in a TK sage or Balance sage's rotation.
If that's the best you can do, I'll direct you toward this thread where you can ferret out arguments against all the posts in there:
As for the Beta: http://www.swtor.com/community/showthread.php?t=168375
Now... please just stop wasting my time. I won't respond further than I already have on the matter unless you've read and absorbed both of the above links.