The problem I see with Mana Adept currently, is that arcane does its max dps by using more mana. The idea of arcane is to make judgements about the situation of when to hold back on mana usage and when to unload as much dps as you can.
So when we are given these 'ways of managing mana' will this mean we are forced into a even more stagnant rotation to maintain mana? Or can we still make the choice of spamming ablast to maximise dps when cds are up.
If Mana Adept is a 5% bonus across the entire mana pool then its barely worth thinking about, and is therefore an almost useless mastery.
Pvp wise, are arcane mages supposed to now go 'omg lol someone to kill AP/Icy Veins/Images/Time Warp/SP trinket/any other dmg cd I've missed, spam dmg lolol' so we can utilise Mana Adept at all?
Other teams will just go 'lolnub' and run behind a pillar/cc the mage/dispell cds.
IF the mastery and arcane mage playstyle was to remain unchanged I don't see how Blizzard could balance without large amounts of QQ. However I'm sure this isn't a finished product, but i hope they don't change arcane into the 'sensible, no, no must conserve mana' spec compared to the 'imma throw away all my mana for big dmg' spec it is now.