Mage Support Counter Meta Change
I find League to be more of a living being. It tends to correct itself. So of course this issue of annoying high damage half carry mage support will eventually be countered. This could be the start of a new META.
High mobility roaming (in conjunction with the JG) assassin support
If you take an assassin style "support" to bottom to start. Get whatever harass you can, then roam between bottom and mid. If this is well coordinated with the JG, you can even own bottom side JG both side. Maybe even bring in some double jg, need to experiment a bit.
If people are going to try and take advantage of bursty support, take advantage of all the extra squishies.