@Riot, what's wrong with Artillery?

I can't but notice how Artillery characters (Xerath, Lux, Ziggs and a bit of Varus and Jhin) tend to be left out of the "Strong" roster and only see the light of tournament/LCS matches on the early stages of a season to be then shelved, nerfed and outclassed by the typical Orianna/Syndra/Corki/Vlad/Ryze/Taliyah picks.

Ziggs saw some play time because of his turret damage potential (which is not needed at all since the few last patches), Varus survives because of his versatility in builds and can build on-hit, Xerath saw an extremely rise in power because of the new Runes but that went away as soon as ppl realized that Azir, Ryze (SpellBook especially), Zoe and Syndra are doing even more damage.

I know that "being sniped from across the map" doesn't sound fun for the receiving hand, anyway I don't see why keeping the Artillery midlaners so out of the meta to the point where their added range becomes a flaw rather than an advantage. We can argue that picks like Ryze/Taliyah/Azir offer more teamplay/roam/pick potential, especially with the mobility at play, but then there are a lot of other picks that should be working better and actually don't (cough Aurelion Sol cough).

So in conclusion, are you trying to keep Artillery under a certain threshold in roder not to make them too popular in common games or are they just a lot unlucky when it comes to high level plays?