I've posted this in a few places but thought I'd start a proper thread on it. I think Skye is too dependent on invisibility, which is too easily countered by Illuminate. I see the value in Illuminate, though, so I suggest a rework to make her less dependent on invisibility without getting rid of it entirely.
First, she needs a two-stage speed buff in her base kit. First to her base speed and also a speed boost when invisible. Obviously her speed-based cards would need some adjustment to keep her from getting too fast. Secondly, allow Skye to double jump off of walls only. So no jumping twice in midair like Maeve, but this would allow her to vault up to low-medium height platforms to get better into the backline.
Secondly, she needs a longer stealth duration out of Smoke Cloud. The reason being that this will be her only stealth skill. Meanwhile, Hidden would be replaced with an aerial jump backwards paired with throwing a handful of those throwing knives she has strapped to her thigh. This adds further to her mobility and escape potential while giving her another small source of damage (100-150 per knife, perhaps, with 3-5 knives in an arc in front of her). The jump would be high enough to get onto low platforms so good map sense would allow for a quick escape into areas her attacker may not be easily able to follow.
I think these changes would fit into her kit and design, still allowing the stealthy assassin approach but also giving her some acrobatic ability to get in and out of the backline with a little better chance of surviving even against Illuminate. With these changes she might finally be meta worthy or at least not a bottom tier champion.