You were right, I just corrected that ^^°
Sorry for some mistakes like that, sadly English isn't my first language...
But nevertheless, thank you for reading my guide so attentively ;)

I can try but while I'm still figuring out how to finish the Support Veigar chapter I also think of wether to implement an extra chapter for Botlane Veigar since it's a big thing in the current meta. But if there are any changes concerning the items or runes of Midlane/Support Veigar, I will always regard that in my guide as soon as I can :)

First, thanks for your feedback on my guide :)
After some rethinking and trying out different runes, I came to the conclusion that Inspiration as the secondary rune path on Veigar definitely isn't the only way to go. It's actually really situational and that's why I changed the runes now: In my opinion, Precision should work very well in most match-ups and it isn't that reliable on the game-time like most of the runes of the Inspiration path.

This is a truly legitimate objection! When it comes to the late game and Veigar has not built a defensive item like Zhonya's Hourglass yet, he already has great damage at that point and normally he does not really need another damage item any more. But still, i would say that wether Veigar should build another damage item (I prefer Lich Bane for pushing turrets) or a tank item like Banshee's Veil pretty much depends on the enemy team, their damage (or tankiness) and CC - and of course your own team comp. Veigar's base stats are not that of a tank and he scales just too well with AP that you have to think carefully about what your team really needs in the respective situation.
That's why in most cases, I choose another damage item instead of a tank item - but as I pointed out, it's very situational. In any case, I will try building these items and expand my guide as soon as I got some useful results.

Thanks for the review!
I recently added the matchups so they are a WIP yet ^^°
In order to provide a rough overview about the matchups, I put all midlaners I could imagine in this matchups-section without going into detail.
Accordingly, I am glad that you shared your experiences with me; thus I can expand my previously subjective opinion and thus improve my guide.
My previous thoughts about Kennen were that his Lightning Rush can be stopped by Veigar's Event Horizon and even in the late game his engage with Slicing Maelstrom could be bounded also by Event Horizon. However, Kennen's build (especially Zhonya's Hourglass) and his mobility would of course counter Veigar.
I will include this in my guide and I also intend to write something to each matchup in the future.

Thanks for reading my guide, I'm glad you liked it ^^

Scaling Health Runes may be a bit risky in the early laning but they quickly outscale the flat runes. Armor is more effective in a long term, laning situation while HP increases your survivability in a burst (in one fight - e.g. ganks or an all-in situation).
So if you feel safe enough and don't expect to take much physical damage before level 6, the Scaling Health is even more useful because it scales up to 216 bonus HP at level 18 (in case you use all 9 Seals of Scaling Health).
To sum it up: If you know you will survive in the early levels and avoid some of the poke, the Scaling Health pays off - mostly in teamfights where Veigar is probably confronted with a lot of burst. In the early game, you want to focus on stacking Veigar's passive rather than going for a lot of trades - so these runes fit his playstyle very well.

Here's an example that compares both Flat Armor and Scaling Health Runes:
You lane against a Zed and he reaches level 6 before you. He instantly uses his ultimate and goes all-in. His full combo would be like 6 hits, which would mean that you take 54 (6 times 9) reduced damage when using the Armor Runes. If you are still level 5 when the Zed engages, the Scaling Health Runes would already have scaled to 60 bonus HP, which is (depending on how you avoided his poke before) more than the bonus armor could do.