Ranger/Ele build

I would like to have a PvE build that is damage based. Hence the idea of a Ranger/Ele sounds cool to me. Here is a build I came across on guildwiki:

http://www.guildwiki.org/wiki/Flame_Slinger

It makes good use of the synergy between kindle arrows and conjure flame. I am a little confused though... kindle arrow is enough to make conjure flame work right? So why would one need Greater Conflagration?

Also I am not really sure how energy efficient this build would be since its not using Glyph of Energy or Mark of Rodgort. I dont really want to start panting for breath 15/20 seconds into a battle.

I tried going through the 25 page monster of a post at the top. It managed to confuse me but I get the impression that R/Me build based on fragility can deal good damage itself. Anyone got suggestions for sucha a build?