Some ideas for abilities
1. A scaling system
This scaling system would fit well on a AP assasin and it would keep them weak on early game so the enemy laner has a chance to shut them down and give them a great burst on late game. This would also almost force the player to avoid tanky builds and focus on ability power so we don't have more assasins that build tank, kill you within 4 seconds and never die.
The ability would deal 50/60/70/80/90 ([{60/70/80/90/100}+{5 per 100AP}]% of AP) magic damage
[lvl1] + 50 AP = 80 magic damage [lvl5] + 600 AP = 870 magic damage
2. A good deffense-offense
I've suggested this one before and i think it could make things more "interesting". The basic idea is a wall that works like a mirror, it reflects (or sends back, in other words) the incomming skillshot and it could also reflect point-and-clicks but that would be broken with things like Veigar's ultimate. I also suggest reducing the damage and cc duration on the reflected skillshot. (Perhaps it shouldn't work for ultimates :/ )
Wall duration: 1/1.25/1.50/1.75/2 seconds Range: 200/250/300/350/400 (400 is the same range as Anivia's wall at level 1) Damage reduction: 90/80/70/60/50% CC reduction: 2/1.75/1.50/1.25/1 seconds (If the reduction is greater than the original CC duration then there will be no CC)
3. PaC skillshot
Simple. A point-and-click shot with big range that stops when it hits any non-friendly unit (minions, monsters, champions). This would create a "need" for positioning. It may be a good combination with the 1st idea ^.
4. Half clone
Note: The only affected stats will be AD, AP, Crit., Attack speed, Lifesteal/Spellvamp, Armor/MR, Leithality/Magic pen., HP/Mana and regen
Yet another clone but a more dangerous one for the user. The user creates a copy of themselves. The stats of the user become half and the other half go to the clone which can be controlled the usual way (Alt + click, ability key). After 10 seconds, the user can click on the clone to merge with it and regain their stats. If the clone dies before 10 seconds have passed, the user gets a debuff that keeps their stats half for the remaining time. If the user dies while the clone is active, they become the clone and they have half stats untill they die. or return to base. While the clone is active, it must be near the user in order to return to base.
5. Double edge
(Point-and-Click) The user becomes connected to the target for [3/4/5/6/7] seconds. During that time, every kind of damage (except true damage) will be shared equally between the target and the user.
So, what do you think? Any improvements?