Should give increased regen the longer you stand still and use it. Start at maybe half the effect, make it grow to 200% after 5-10 seconds ? 

I disagree, There are already many ways to increase SP: SP leech weapons, Concentration when out of Battle and Total Restoration Potions. Everything is currently balanced.

Who said anything about SP? I run out of mana way faster. Are you a Wizard? Do you use spells for everything? Do you spend 80 seconds sitting to get it back with 200 conc and maxed regen? I cant even carry potions on Corsix with the weight of reagents at the moment. Want a wizard to use a mana leech staff? pointless !

Reduce the starting recovery by 50%, so you have to sit for a little longer to make it good, but can refill much faster if you do. Makes it better for refilling mana instead of just topping it off

Then Increase you Strenght and Stamina and carry Mana Restoration Potions level 4 or 5. Concentration is balanced as it is. Wizards need more status points than any other class to work properly.

Stamina wont help, if i could afford to pump strength i would carry more reagents so i can hunt longer before refilling.

 

Granted you may be right that Concentration itself is not the problem, and the real issue is the lack of Wizard specific gear, MP regen/max MP Robes and Wizard Hats or Leather. I've never even bothered wearing anything besides Leather since 'being hit' isnt in the plan. When specific robes and unique hats are added, it may make up for how long it takes to regenerate even at 200/200 conc when you have 120+ mana. It feels like doing less damage than a barb and then lots of waiting.