You apparently never played a Powertech, or researched the ability. Grapple is only reliable 50% of the time, and it is negated by resolve.
Grapple is also only an "instant kill" in Huttball, and Huttball alone, under special circumstances (fire/acid.)
You're asking for 2 DPS abilities to be allowed in PVP, because of one ability another class has, that works in only one Warzone.