If you could change one thing about the Rogue what would it be.
Its existence.Remove it from reality, replace it with the Slayer retroactively.
Despite the pooh-poohs this comment has received, I agree wholeheartedly.
Much like the PrCs in the CRB, the Rogue is a relic of 3.5 that unfortunately hasn't aged well/remained relevant.
The slayer is what a combat oriented rogue should have been all along. Currently, the rogue class is deadwood. The only point in playing one is to do a slayer/investigator multiclass without the pain of multiclassing.
Rogues aren't thus COMPLETELY pointless, but that's not much of a reason for the class to continue to receive time & energy from Paizo. It'd be far easier to just rename either investigator or slayer to "Rogue" in order to honor the legacy of continuity the class.