Alright so the vigilante has several class abilities that operate off of surprising the opponent, four to be exact including his capstone!
However he lacks any real means to remain undetected and get that surprise in the first place. Especially in a pathfinder world where darkvision, blindsense, blindsight, and other various senses exist.
Yes the vigilante can use stealth but he lacks anything to actually make him good at it as a class. Some of the specializations have some options (vanish and invisibility for the warlock, a bit of hide in plain sight for the stalker), but for a class that has several major features that are core functions of the class (meaning every specialization gets them) it is lacking support for this key feature.
As such I would suggest if these class features are going to stay, and stay how they are the vigilante needs means to be better at stealth and to get the drop on his opponents in the first place, and a means to do this even as the rest of the non-vigilante party is doing whatever it does.
If this is the direction and features the vigilante is going to push he needs a mechanic or a better means of using the existing mechanics to do so.