Getting mana back on an auto attack... about as interesting as Lissandra's old passive giving her a free spell.
They reworked 
, but 
was forgotten.
With how much mana you can get back from Lost Chapter or even just the Manaflow Band rune... is there a need for his current passive?
It was an incentive to leave his max range to auto someone/something. If it had an appointment scaling and some damage added it might do that again
Well in his current state Xerath really needs this passive. It simply cannot be removed without reducing his costs big time, or giving him another form of manasustain.
Still in the end his current passive is not additional power for him, but actually something that holds him back. And that's definitely not what you want your passive to do...
Imo the passive is okay. Sure you get a good amount of mana from Lost Chapter and Manaflow Band, but when ure against assassins on mid where you need to rush zhonya its pretty useful.
Not to mention it's great on supp xerath.
