Why just have 1% mana leech on items?

Hey,
I thought in previous versions there were items with more than % mana leech. Do you want the players to really use their mana flasks? ;)
I think some players could find it annoying to drink just every 2-6 seconds when fighting a larger group of monster (that's what I have to do with my duelist on merciless, 400 mana pool, ~60 mana each attack, >2.2 attacks per second and just 2% ml Warlord's Mark). I don't have a problem with that, but it would be interesting to know why there is just 1% ml.