Not weak, but that's not how the Thief works in the Pnp. His second-story work and bonus sleight of hand are supposed to be used in dickish moves like hitting and climbing up a tree were an enemy can't reach you or use sleight of hand to rob an enemy of his sheated weapon. The thief in the Pnp is not a DPS class, Assassins and Swashbucklers do that, they are more about cunning and creativity.
This is an example of a fundamental mechanical change as the class plays very differently in the game compared to Pnp.
I totally agree, that's not how it works in PnP at all. I was just adressing this:
Thieves also gain a second bonus action instead of second-story work, since there is no climbing, cunning action only works for Dash as Hide and disengange are bonus actions for every class, which makes the Rogue weaker in comparison.
Also thief is extremely mobile, because they can use bonus actions to dash. They can do things like:
1) Double dash and attack someone.
2) Dash in, attack and dash out.
3) Attack someone and double dash disengage.
Moving in and out of enemy threat range without attacks of opportunity.
Just all around insane mobility.