I won the Slave at one of the KR events I attended, but haven't played with it outside of the two grand final matches yet. With that being said, it is a toss up on the pilots for me. Though I did love using Kath in the final, I found that the build they gave us (Heavy laser cannon, mercenary copilot) didn't cater toward her ability. In fact playing the Imps in two grand final matches, it never came into play once. The problem is that as awesome as the HLC is, you can't get crits, except 1 at range 3 if you have the mercenary copilot or 1 on a focus with marksmanship. So in order to make use of Kath's ability, you either need to be using just her primary weapon, or secondaries that can do crits. So now I look at Boba Fett, and he only costs 1 point more for an extra pilot skill and an ability that I personally find indespensible. If you play the game well, you don't need me to tell you that maneuver is absolutely the most important part of being successful at this game. Krassis is so close to being awesome. I'm not saying he is bad, and he has a solid ability, but only a mid-range pilot skill and no medallion icon. I would take him without a second guess if he had that medallion icon and I could throw marksmanship or veteran pilot on him. Now of course I'm not taking synergy into account with anyone, because you could easily have Krassis hitting at step 8 or 9.
Of course the Slave (and Falcon too) can become easy focus targets, but after playing a 3 ship Rebel list (where every ship is going to be 30 or more points worth) so is Wedge, or Horton, or anyone else for that matter. If you look right at the base stats of the Slave, it is an x-wing with doubled hull and shields. So that gives it probably around double the survivability, when you consider it has evasion but x-wings can take droids. Krassis with a HLC is only 7 more points than the Wedge I brought to KR.
The bottom line is that from my experience so far, this game is very well balanced, and the new wave is no excpetion. Just look at the KR thread and check out the myriad of different lists that the winners used. It comes down to making a list that can work together, yet where no one model is the lynchpin (this is why I would never, however, field a fully kitted out Fett), and player skill.