Weeeell, it's not entirely fair to classify TT Robin as such, seeing how he can kick himself off one humanoid robot to the next while taking their heads off, or deflect "laser" blasts by spinning a staff, and other such cartoonish feats.

I think each Robin truly is that "one" street tier you REALLY don't want to mess with. Consider this:

Dick Grayson - Is a world-class Acrobat (Dexterity)
Jason Todd - Had the guts to steal the Batmobile's wheels (Tenacity)
Tim Drake - Was able to figure out Batman's identity and that he needed a new Robin (Intelligence)
Damien Wayne - Is a master assassin and the rightful heir to the league of shadows (Skill)

and THEN they receive training from THE Batman and work alongside him. Its like if the Punisher was taught by Iron Fist all of a sudden (which he might of been considering all the comics out there nowadays); you just took a grade A hero and made him S class.