Is Ziggs considered a counter to common mages?

He outranges most champions in general. He is more of a "Do I enjoy playing him?" champion

I would say no because ziggs is just not very good right now. He relies on spamming his Q to do most of his damage, but his hit box its so tiny now it is really easy to dodge.

ziggs is for harassing short range champs, waveclear/holdin towers or being overly safe in lane. or all of them if u got a blue buff.

I wouldn't say so, his Q isn't as reliable as say Xerath's Q or Azir's Q