So just because someone made a mistake, they'll make that mistake again? FFG did playtest it, but there is a VERY big difference between getting 20 people to test your product, and then putting it out in the hands of hundreds if not thousands of people. Balancing games is not easy and requires feedback. Yes, the JumpMaster was a mistake. Will they make another? Who knows? I hope not.
If you don't trust FFG...I'm sorry but why are you still here? If you don't trust the designers then you don't have faith in the game or it's future and if it bothers you that much...it's time to call it a day.
The fact of the matter is, we don't know anything about the design process and if we assume things, we know the saying: assume makes an *** out of 'U' and 'Me'. For all we know FFG playtested the JumpMaster, and it passed all because the playtesters (who are players in our own community I will point out) missed X, Y, and Z combining to make: OP.
We can't be sure if they adiquately tested it or not and to pass judgement on that means nothing. The only thing we can do is test it ourselves. If you truly and utterly believe the ARC Caster should be permitted for Imperials and that people are wrong that it will break the game...then prove it! Playtest it yourself and give us the results. I'll be all too happy to hear about your findings.
Also, flying out of formation as a counter tactic...yeah..fantastic if you are running a synergistic list that relies on you being close to each other.