Do Not Ruin Vel'koz
As most of the community is saying, velkoz is in a good spot right now and has NO REASON TO BE REWORKED. He is fair to play, fair to play against, and though riot would say he has nothing unique, that is false. His passive gives good true damage for using it right and his ultimate and combos can drastically change a team fight.
If you are going to do anything to him the only thing I could suggest is making his passive have more to do with knowledge and learning about his enemies. Maybe something like: If you hit a target with all 3 procs you do more damage to them for the next couple seconds to signify that you "learned them".
The whole thing really does come back to riot listening to us in big things they have planned and them being willing to change for the players. If all goes well, hopefully this will turn out as a much better update than the previous "Juggernaut" group rework.