Low winrate =/= less counterplay. For a while Azir had a very low winrate but very low counterplay. Old Yorick had a low winrate but almost no counterplay.
#1, azir had a low winrate because because he has to do TOO MUCH to be effective, so he was popular in high levels and professional play. Tryndamere and Yi have low win-rates because they win by profiting from their opponents' mistakes and not from having effective tools in their kits
Master Yi has a blink that resets and can be reduced through kills. Tryndamere has a dash that is reduces through auto attacks.
#2, Yi's Q cooldown is reduced by attacking and not from kills; Tryndamere's Dash is reduced by 1 second for critical hits or 2 if he has guinsoo's rageblade in effect. Yi's Blink only functions while in range of his opponent or a minion he can damage
Literally the only thing in their kit you can play around. Too bad 90% of their damage is targeted.
#3, marksmen have 90% of their damage as targeted as well and have higher range. If you change melee, marksmen need to be changed as well
This plays back to them being melee.
#4, you did not disprove my point, only pointed out that they were melee
This is not counterplay. Once they get these items, this goes away. This is a weakness, not counterplay.
#5, item dependent is very much counterplay, as it has been since the beginning of league. DO NOT LET THE GAME LAST TO THE POINT WHERE THEY REACH A PEAK OF POWER. Tryndamere is a split-pushing champion and only relevant so far in a team fight. Master Yi has only one strength: his ability to take out a target. If you punish his lack of gold, he can do little about it. If the game lasts too long, if he's stopped via crowd control or just pure damage, he has no utility to offer his team
I don't see how this is supposed to help me avoid or outplay them.
#6, this was listed more as a weakness than a method of counterplay, but if the team does not attack them while they are attacking a team member, that is the team's fault and not the champion's. Master Yi and Tryndamere can only attack one champion at a time and are prone to interruptions, counterbuilding, and of course, proper positioning.
#7, Darius plays much the same as tryndamere but he trades having SOME mobility for having MORE damage and DURABILITY. Illaoi is currently a champion of debate because she has clear moments of weakness, BUT, when she is not having one of these moments, she becomes a champion that is "avoid at all costs until she loses her ultimate" which is unhealthy.
#Here's a point I think you missed in your own explanation: "telegraphed and delayed damage." Unless you are facechecking near an unwarded area, Master Yi and Tryndamere have very binary kits that are predictable because it is a core part of their engage.
You're confusing an overpowered champion with a champion who was no counterplay.
#8, really? Aatrox could ONLY be kited during that period. He had to be killed THREE TIMES and was a monster because of it during team fights. Tryndamere and Yi both can be crowd controlled and put out of action when killed. Aatrox only waited it out and the fight was over, or you were run under your tower and the game was done while they busted down your base defenses UNLESS OF COURSE, YOU WERE FOOLISH ENOUGH TO FIGHT AATROX, IN WHICH CASE, HALF YOUR TEAM GETS WIPED BY HIM ALONE
#9 here's a fun fact. Master Yi and Tryndamere are DUELISTS, as are fiora, jax, riven and multiple other champions. If ANY OF THEM catch you alone, you are going to die. DON'T DUEL THE DUELISTS! that is their one and only strength: taking out a single target at close range, which riven was long-criticized for because she can do more than other duelists and has an ult that can cause a large amount of Area Damage