Short answer? "No."
Currently Champion Update (ChampUp) believes that a "Traditional" skin is warranted only when they alter a champion too much from their original vision:
- Karma received one because a ton of things changed on her, including the fans and the grey/black default outfit.
- Sejuani received one because the art team wanted to move away from the original "Fur Bikini Ice Warrior."
Trundle received one because GrumpyMonkey pretty much lied that Trundle would remain the same "loveable poop troll" months before the "Generic Ice Brute Troll" rework was announced. The "Traditional Trundle" skin was supposed to be an appeasement, but wasn't much of one given how the rest of the rework went over with fans.
- "Traditional" Lee Sin was supposed to be the default skin before they came up with the current "Blind Monk"
When ChampUp doesn't feel like they've altered the core concept enough, no Traditional skin will be given.
- Sion, the best example of this, received a huge change to his kit and artwork with his relaunch. However, since the core concept of Sion is a giant, undead juggernaut, they didn't feel like he warranted a "Traditional" skin.
So, unless Tristana changes significantly from "jumping long-ranged player killing reset machine," there won't be a "Traditional" skin.