If I max mp and use ring with bloodmagic what will happen? Is my DMG will be same? Oh damn I was thought my gives attack to wiz 
Your dmg will be different since your MP is converted to HP and if you have missing HP (say from thorns, an enemy attack or sanctuary), you will gain more DMG. Only downside is doubled spell cost. Survival will be fine as long as you can dodge/block with dodge or block affix and as long as you can defeat enemies quick enough or slow them down/stun them.