I see everyone here complaining that the investigator has sneak attack or that he/it has too many dice for it. At the same time, I hear people complaining that rogues suck and nobody wants to play them. In my opinion leave the sneak attack alone and this makes a viable substitute for the rogue. I have several reasons for saying this, but the big 3 that jump out at me are:
1: This is a rogue hybrid. It's supposed to have sneak attack.
2: If you take sneak attack away from this class, it's extremely weak in combat.
3: Vivisectionist was taken away from PFS players. In my opinion (and many others out there agree with me) the vivisectionist was only the way to fly for melee alchemists. If you leave sneak attack in for the investigator then that build becomes viable/playable again, particularly in the PFS arena.
I do agree that poison use is unnecessary and can/should be swapped out for another option.