Sivir Spell Shield (Gameplay Upgrade Idea)
It is a great skill of course, but I see that it has remnants of old Sivir
lore, when she was a bounty hunter and had nothing to do with Shurima and the desert.
This is the current [E] skill.
**Spell Shield ** ACTIVE: Sivir creates a magical barrier that lasts up to 1.5 seconds, blocking the next enemy ability used on Sivir. If an ability is blocked by the shield, Sivir gains mana. MANA RESTORED: 80 / 95 / 110 / 125 / 140 COOLDOWN: 22 / 19 / 16 / 13 / 10
Spell Shield is an interesting defensive skill to the old Sivir, but now the skill can have a much greater thematic appeal and more interesting gameplay.
The suggestion would be to continue a defensive skill, but add a thematic effect related to Shurima desert. 
New [E] skill.
**Mirage Shield ** ACTIVE: Sivir creates a magical barrier that lasts up to 1.5 seconds, blocking the next enemy ability used on Sivir. If an ability is blocked by the shield, Sivir instantly becomes stealthed for 1.25 seconds and gains mana. MANA RESTORED: 80 / 95 / 110 / 125 / 140 COOLDOWN: 22 / 19 / 16 / 13 / 10
PS: the 1.25 secons time of stealth is only a suggestion, all numbers could be adjusted, what matters here is the thematic evolution of the skill.
The ability would possess some fast opacity visual effect as the Sivir model disappearing just when the Mirage Shield blocks a skill. Seriously, her weapon is some kind of magic Shurima key, even during the in game animations, you can use [Q] Boomerang Blade and still perform an auto attack, or even use 3 times in a row Ricochet, how can there be so many blades? Her weapon probably has some power of the desert mirages.
Thanks for reading and I'm sorry for any grammatical error.