What exactly is the problem with Vel'Koz though? Sure, he mainly just does damage, with a little bit of CC attached, but all his abilities are skillshots that work differently from one another and he is rewarded by hitting multiples of them in a short timeframe. This makes playing as (and against) him largely a matter of hitting/dodging various different kinds of skillshots, which is fun to play as and not really unfair to play against. His ult is very satisfying as well.
So... what's the problem with Vel? Is it that his fantasy is incomplete because desintegrating enemies does not actually make you smarter? :derp:
I could go on for quite a while about Vel'Koz's problems as a Mage specifically.
But here's the Core one:
Fantasy Pushed in all promotions and things: DESTROY THEM WITH LASERS
Life Form Disintergration Ray: 1550 Range; 2.5 sec
channel; 0.6 AP ratio over that duration 130/110/90 C/D
Final Spark: 3340 Range;
Burst Damage; 0.75 AP Ratio with potential +0.2 from passive proc and applies passive for another effective 0.2. 80/65/50 cooldown
Vel'Koz's damage is all bundled into base damages. His AP ratios range from merely acceptable [Q] to a joke [R]; which makes him scale really; really badly with AP in comparison to other Mages in his niche. When the fantasy pushed by all the promotion is LIFE FORM DISINTERGRATION RAY and yet an already existing champion already does that, as their Ultimate, in a more satisfactory manner ... you have a problem.
The fact that a spell with a 2.5 second channel and half the range AND a longer cooldown scales worse than Final Spark does is an absolute joke. 100% of the time; assumeing the damage is equal; Burst is preferable to DoT [And no; Steraks dosen't count all DoTs do damage in quick enough intervals that it'll not reset]. Especially when the DoT can be canceled by C.C. That's why we had League of Thunderlords and not League of DFT. Because Thunderlords is Burst.
I mean what feels like you're getting disintegrated more? Getting Final Sparked and chunked or getting slowly ticked down by LFDR?
I mean watch
First Contact again. What is the only ability Vel'Koz shows? Look at how devastating they make it look. It's literally carving and melting the ground under it without even touching it. But in game? It's underwhelming. Even in the champion Spotlight Summary; Phreak introduces him as 'Armed with an array of lasers' and 'fires abilities to keep his enemies at bay while he primes his DEVASTATING Ultimate'.
But that's the thing. For all the buildup; his R is a really big letdown.
His other issues include Waveclear vs Harass [Which he ignores as a Support]; the fact that he gets 10 True per level but every champion gets far far more than 10 HP/Level so his passive actually negatively scales in terms of
relative power; and his R base damage is 500/700/900 meaning Vel'Koz peaks at Lv 6 [His full spell rotation is avaliable so he can apply maximum passive procs at 6; but his negative passive scaleing combined with his lacklustre R ranks after 1 makes his relative power gain after 6 a lot, lot less.] and starts going downhill in relative power from there... which is pretty dumb for a midlaner [But great as a support]
I mean he's also only pushed as a midlaner in all the promotions and his reveal page. He is most commonly played Support because of his lack of scaleing and the simple fact that he gets to ignore his issues as a Support. Vel'Koz in a midlane; given farm and solo XP is a waste of resources compared to other Mages in his long-range niche who gain more power from levels and AP than Vel'Koz does.