Kassadin Jungle Devourer

I look at list of champions to play in jungle in actual season and find kassa and decided to play him devourer , for bonus damage on W passive, IS this good idea ? or i should build it in runeglave , so can he build like kayle AS ? AND is Kassadin a good jungler ,( his E is practicly uselees until u get more cdr), (Passive give MR that is useless in jungle clearing ) (Q have MS that is used only vs AP champions).SO kassadin will be fine only in team fights post 20 when he will get 2-3 items .