Edit: Woah, downvoted. I guess asking questions to learn about the game is prohibited. Sorry. Kappa.
2nd Edit: So the main reason that Vel isn't picked is because there are better options with better tools. What would need to happen to Vel'Koz to make him as viable as other mid laners?
I typically only see him as a support. He's a decent support, but I've played him mid, and he seems fairly decent. Can someone explain why he isn't played mid?
oSEXYPLATYPUSo1 voteswhy play a harder champ when you can go to lane as 
and press R
SEKAI1 votes[{quoted}](name=MrFawknSunshine ,realm=NA,application-id=3ErqAdtq,discussion-id=uTemt0vg,comment-id=0000,timestamp=2017-07-04T19:10:47.053+0000)
why play a harder champ when you can go to lane as
I've been playing Malz mid lately, and R does surprisingly low amounts of damage by itself. If you actually want to burst your lane opponent, you need to E, W, R (full channel) and then send them with another Q to hopefully "burst" them.
So it may look simple "hur hur I pressed R", but not really. And it's not like Vel isn't a "press R" champ given its power and the fact it also slows people in it.
Vel is pushed out of lane mostly because he has less ways to keep enemies at bay than someone like Malz.
oSEXYPLATYPUSo1 votesmy point was malz is safer and a simpler champ then a velkoz
it wasnt to take away skill from said player playing said champ...
it was an example
SEKAI2 votes[{quoted}](name=MrFawknSunshine ,realm=NA,application-id=3ErqAdtq,discussion-id=uTemt0vg,comment-id=000000000000,timestamp=2017-07-04T19:28:31.527+0000)
my point was malz is safer and a simpler champ then a velkoz
it wasnt to take away skill from said player playing said champ...
it was an example
Yeah Malz is definitely safer and overall less tricky to use (at least Malz doesn't have something as tricky as Vel's Q and something as situational as Vel's W).
Given that Malz has a passive spell shield and Q breaking people's burst combo when jumped on (and R can also be used defensively if have to too), Vel only having that telegraphed knockup pales when it comes to emergency (unless you want to "CC" the living fk out of enemies by R....) pales in comparison.
Vel's solo survivalbility needs a buff or tweak, I would say. But hey.
HudnofskiBleh1 votesThanks for the info guys.
SchmidttyGames1 votesHe gets hard-countered by to many meta champions right now. His lack of mobility is a real problem in his kit when his damage can be gotten on someone with greater safety.
Inting Pillow1 votes
is like a Vel'Koz with seige and mobility in place of true damage. And he doesn't require you land that knockup. Why 
when you can
Zane Zephyr1 votesHe has no mobility, reliable cc, any means of self preservation, and his damage doesn't come out that fast
assassins shit on him super hard
Dark Nephthys1 votesVel can still be played mid and do well though, he is my 2nd main mid laner but yea his match ups can be a bit rough at times. As mentioned, the main reason he isn't played much is because there are better options that do the same thing he does and Assassins are really annoying to play against as . Though once you get used to him and his match ups, you can really carry games with a well timed knock up into ultimate.
Vanic9981 votesI'm a Vel'Koz main so I'll give you an in depth reason. When people say that other mages do his job easier and safer that's very true. Unlike most other mages, Vel'Koz can't kill you with one combo because Vel'Koz's knock up is for some reason only .75 secs and Vel'Koz's ultimate deals damage over 2.5 secs so if your enemy has flash or a mobility move, he can still avoid a lot of his damage even if Vel'Koz lands all his basic abilities (qwe). From my experience, in lane you have to use your ultimate as an execute rather than relying on the full channel by poking your enemy first so your enemy is low enough for your ultimate to kill them in the .75 secs provided by your short e suspension duration. Other mages can actually kill you from full hp if they land their combo. From my experience, if brand or Syndra land their stun, their stun duration is long enough for them to use their other basic abilities and ultimate AND ignite and you'd die. I'm not complaining though. It's for this reason that makes Vel'Koz balanced and fun and fair to play against.