First of all I'd like to thank Riot for giving Kassadin a new and improved, more risky feel to his otherwise super safe playstyle. I'm sure most people would agree with this and I can definitely say he feels a lot more engaging.
That said, however, I feel very unsatisfied with new Kassadin's damage output. Even when fighting in melee range, his damage output just feels....insignificant. I had my fair share of issues killing beginner Sona Bot in custom at full build. Looking at the numbers, I've been able to figure out why his damage output is so terrible:
**RQE and one proc of W**. Riftwalk stacks not counted. Physical autoattack damage not counted since his AD/AS isn't changed at all (although he no longer gets AS from his passive). All skills at max rank.
Live Total Damage: **650 (+2.5 AP)**
PBE Total Damage: **600 (+1.4 AP)(4% total mana)
Live RQE and no W:
**560 (+2.2 AP)**
**Approximate damage after ~5 seconds** (~5 autoattacks with W on Live, 2 casts of W, 4 unempowered autoattacks (added 1 more total autoattack compared to live due to reset) and one extra cast of Riftwalk on PBE). No cdr is involved
Live: **1010 (+3.7 AP)** |[ (120 + 240 + 200 + (90 x 5))(0.8+0.7+0.7+ (0.3 x 5)]
PBE: **980 (+2.2 AP) (6% total mana)** + ~110 physical damage from the extra autoattack | [ (180 + 180 + 120 + 180 + (120 x 2) + (20 x 4)) (0.5+0.5+(0.4 x 2)+(0.1 x 4)) (4+2% total mana)
Something to keep in mind here is that **Kassadin's W passive does not stack with its active**. I was wondering why I felt like I did little damage with W, and after checking its damage on monsters I found that out. I'm not sure if this is intended - I assumed the damage would stack since the tooltip did not state otherwise.
Now that right there is an absolutely massive damage difference. While it is true that Live Kassadin does absurd amounts of damage and warrants a nerf, PBE Kassadin's damage is not rewarding at all even if you keep fighting in melee range. **Losing out on a pretty chunky 1.1 AP on burst and ~1.5 AP on sustained damage for 4% and 6% max mana extra dmg respectively **is quite a ridiculous loss. And that's not counting the attack speed granted by the Live passive.
There are a few other things I did not throw into the calculation, such as being able to stack Force Pulse easier with the new W (ultimately doesn't make a whole lot of difference since it stacks off everything around it anyways, and Force Pulse does a lot less damage now), Lich Bane dmg (not sure how much of a difference this would make, not sure if it's even a core item) and Live Riftwalk stacking, and probably a few minor things. Anyways, while I do feel that this rework is going in the right direction, I do feel that his damage loss is rather extreme.
That's not to take away some of the perks of this rework of course, including more short time mobility, increased movespeed and range, and a nifty new shield mechanic
My 2 cents.