Force-sensitives (Star Wars); via the Shatterpoint technique
Zer0 (Borderlands 2); via Deception and Bore skills
Delsin Rowe (inFAMOUS: Second Son)
Abigail "Fetch" Walker (inFAMOUS: Second Son)
Mega Man (Mega Man); via E. Analyze
Bass (Mega Man); via E. Analyze
Model H (Mega Man ZX/Advent)
Fuuka Yamagishi (Persona 3)
Wander (Shadow of the Colossus)
Flandre Scarlet (Touhou Project)
NaNaNa (Bleach) can use The Underbelly to detect the weak points in an individual's Reishi to attack them at those points.
Using his X-Ray Vision, Superman (DC Comics) can scan his opponents for weaknesses, allowing him to perform such feats as precise lobotomies, as he demonstrates on Doomsday...
...and Manchester Black.
Wall Eehto (Fairy Tail) is a Mage that mastered Weakness and can extend it to his Machinas which allows him to see the weaknesses of his enemies while creating soldier to counter their magics, while he can alter his own form to overcome his own weaknesses.
Delsin Rowe (Infamous: Second Son) using Laser Insight to detect weak points in his enemies, allowing him to non-lethally subdue them or simply kill them.
Unlike her father Spider-Man, Spider-Girl (Marvel Comics/MC2) can use her spider-sense to detect weaknesses in her opponents and exploit them.
Using his heightened senses, Matt Murdock/Daredevil (Marvel Comics) can detect and exploit his opponents' weaknesses, demonstrating with Brusier's ability to manipulate his center of gravity.
Users of Model H (Mega Man ZX series) can use Enemy Analyzing to find an enemy's weak point.
Using her Magic Eye, Mio Sakamoto (Strike Witches) can detect the weak points of Neuroi.
Luke Skywalker (Star Wars Legends) using Shatterpoint to destroy some battle droids.
Cade Skywalker (Star Wars Legends) using Shatterpoint to destroy the Muur Talisman.