Sylas Rework Idea
Right now, Sylas's ultimate doesn't really fit in with the theme of his champion. Instead of changing his ult, however, I think that his theme should revolve around it. This reworks aims to make Sylas's theme more prominent.
Passive Hijack Passive: Whenever Sylas uses a basic attack on an enemy, he steals their passive for 15 seconds. Additionally, Sylas automatically gains the passives of enemies within 2000 units of him.
Q Hijack Q: Sylas steals an enemy's Q ability. The Q ability he steals is empowered to additionally slow enemies hit by 20/25/30/35/40% for 2 seconds. Individual enemies cannot have their Q hijacked again for 200/175/150/125/100% of their Q cooldown, affected by Sylas's cooldown reduction. Cooldown: 10/7.75/5.5/3.25/1 second
W Hijack W: Sylas steals an enemy's W ability. The W ability he steals is empowered to heal him for (40/50/60/70/80% AP) when cast. Individual enemies cannot have their W hijacked again for 200/175/150/125/100% of their W cooldown, affected by Sylas's cooldown reduction. Cooldown: 20/15.25/10.5/5.75/1 second
E Hijack E: Sylas steals an enemy's E ability. The E ability he steals is empowered to give him a 50/70/90/110/130% AP magic damage shield for 3 seconds. Individual enemies cannot have their E hijacked again for 200/175/150/125/100% of their E cooldown, affected by Sylas's cooldown reduction. Cooldown: 13/10/7/4/1 second
Ultimate Hijack: Sylas steals an enemy's ability (he can choose which one). The hijacked ability is empowered to deal 25/30/35% increased damage. This ability ignores individual cooldowns of hijacking specific enemy abilities, but Hijack puts its own cooldown on the enemy for 125/100/75% of the stolen ability's cooldown, affected by Sylas's cooldown reduction. Cooldown: 30/16/2 seconds
This rework was meant to emphasize Sylas's ability to steal abilities from enemies, while keeping some of his perks (like his shield and healing) that he current has.