Ults have at least a 30 second cool down.
Silence abilities do(did) not.
Tryndamere is fairly balanced; due to the current state of power of Marksman, melee NEEDS to have some kind of damage negation skill such as: Alpha Strike, Wind Wall, Blade Waltz, or Undying Rage to even get close.
Kayle's shield is arguably the only useful mechanic she has in a team fight, plus it is unique and lasts only 3 seconds. Its effect is no different from GA or Zhonyas.
Aatrox's passive also gives him AS. When he loses all these bonuses from his blood well, he becomes severely gimped in combat potential. Even then, it has a fairly long cool down, and the enemy team can just pounce on him once the animation ends.
With each of these champions, it is also always an option to simply disengage. However, with Talon and LeBlanc, the only counter play is to not die from their burst. Talon's cut throat allows for absolutely no chance of counter act or escape, while he can cast his ult for further mobility. LeBlanc had two free flashes worked into her kit and a long range silence in addition to high burst.
If you think that any of these "victim" champions were over-zealously nerfed by removing their silences, well, I agree with you.
However, please don't even juxtapose these champions to Tryndamere or Kayle, they are not even remotely close to how powerful Talon and LB was.