Given that most kill-lane supports are out of meta, it's surprisingly hard to get any wave clear as a support. Try doing a wave clear as Janna or Soraka when your runes, masteries and items are optimized for support.
Sadly, I'm starting to suspect that the push towards more supporty supports is making it harder to actually climb in the support role. I've been watching the "bronze to diamond" and "unranked to diamond" streamers this season (after my last 7 out of my 10 placement games featured afks, trolls and other lovelies, and I started my ranked on this account a bit late due to university). And, it's not hard to notice that poke and kill champs (e.g., Zyra, Brand, Zilean, Morgana, Velkoz, Annie) were the main tools the higher tier players elected to use for their climbs when they had to play support. (As a sidebar, it was especially funny watching one master player in a support only run when he chose Janna at bronze tier in one game.)