And the Fact that DragonSage HP+MANA-Leech is permanent in Evo not ever xx Seconds^^ outside elemental dungeon you can prettymuch freely spam you skills and never run out of mana or hp(if you dont go vs mobs that you shouldnt tackle for farming anyway xD)
For me DragonSage on lvl 80 is pretty much perfect in pve, its tanky, it has aoe and it can sustain it self. Downside is that before Evo-Passives are at Decent lvl it takes effort to get there.