I lose so much to Tristana, that champion feels super oppressive. As someone who plays melee champions, I sincerely feel that she is god damn nearly unreachable. Without Flash, there's no way to get her late game because of her ridiculous range. Then, even if you can reach her, she has too many tools to get away from you. She can Rocket Jump, Flash, or knock you away with Buster Shot.
It's not like Tristana's "kit" is weak by any means. After Tristana's little bomb rework, she gained far more power than she lost. Tristana literally kept every ability in her entire previous kit, with even more added on it. Let me tell you, it really shows too. Not only in professional games.. where she is picked constantly, but also in everyone else's games. According to OP.GG, Tristana is still sitting as the 3rd most winning ADC.. that's even after getting nerfed.
All the players spamming that freelo Tristana will hate me for saying this, but I honestly believe that her extra "range" passive should be removed. Tristana gave up nothing for that extra power on her E and it doesn't feel fair at all that Tristana can have that insane range and also still do massive damage to players and towers (even at the same time), without having to worry because if someone gets close she just jumps back or shoots them away with her ultimate.
Caitlyn is supposed to be the "long range siege" champion in League of Legends, yet she doesn't do anywhere near the damage to towers. Caitlyn can't knock you away, her E animation is fairly slow, she's far weaker than Tristana who wasn't initially even meant to fill that role (and yet does better at the job than a champion supposedly created for it). Sure, it's not really a big deal if there are multiple champions who are "siege" champions, but Tristana simply has way too much range and safety for the amount of damage she deals late game.
Maybe I'm crazy, and this isn't the right answer, but I don't think Tristana will lose much if her range is taken away. She'll still be very strong, the only thing that's going to change is that Tristana players won't be able to just go on auto pilot once they have a lead and fall asleep hitting the A button on everyone from a mile away.