Okay, here's my challenge to the Pathfinder community:
Using the least amount of new rules possible, what would you change about the existing classes to fix them? Keep in mind, "fixing" could mean nerfing, buffing, or altering a class's focus. Optimally, such modifications would be cut-and-paste features from other classes, if only to reduce the potential for strange interactions with other parts of the game. For example, here's my idea on how to fix rogues.
Ambush: For purposes of sneak attacks, the rogue's base attack bonus from rogue levels is equal to his rogue level. For all other purposes, such as qualifying for a feat or a prestige class, the rogue uses his normal base attack bonus.
Canny Defense: When wearing light or no armor and not using a shield, a rogue adds 1 point of Intelligence bonus (if any) per rogue class level as a dodge bonus to his Armor Class while wielding a melee weapon. If a rogue is caught flat-footed or otherwise denied his Dexterity bonus, he also loses this bonus.
There, two little additions that I think would go a long way toward making the rogue class more attractive. Most of the complaints we see have to do with the fact that rogues, while skilled out of combat, are way behind the curve on the battlefield due to their medium base attack bonus and low armor class. So, instead of trying to reinvent the wheel, we've simply brought over effective mechanics from the monk and duelist to fill those gaps.
Anyone want to give this a shot for the other classes?
I could see letting ambush work if was only in surprised rounds. As a Rouge Talent. Also I would make be Situational bonus equal to 1/2 you rogue level. This would net you +5 above full BaB PC for one shot per fight at 20th level. IF you can set up the Ambush....Hell still my say no to that one because it would be more likely be used by GM than PC. Since How often do PC get to act in the Surprised round vs GM Minions.
For Canny Defense add if you are not encumber...
You're kidding, right? That would hardly be a rogue fix at all. The problem is he already has to work to be situationally useful. Other classes aside from the Duelist get a version of Canny Defense (like the Kensai, for example) and it doesn't hurt the Duelist at all. And make it a rogue talent? You may as well not change the class at all.