User blog comment:RoznosicielCiast/One day without Ignite and Flash?/@comment-5514182-20130603222524

Flash is just too strong to not take. I played Jungle Jax and camped the enemy leblanc who had brought Ignite+Barrier, crushing her.

Ignite is also favored for killing potential. Renekton for example gets fed off kills early on, so picks up Ignite even if Exhaust or Teleport or Ghost would be more useful lategame.