Mechanicswise, I'd speculate that Mana isn't regarded "as important" as Health, and that a lower regeneration is meant to make the players economize their powerful spells. Remember: you can always use your staff for free ranged attacks that don't cost anything but the action itself! Anything that consumes MP, however, is something special you're supposed to use rarely.
Doing so would result in a situation where the party, in particular its melee combatants, will use up more Health than Mana, so the system is geared slightly more towards the former. At least that'd be my guess for why things are how they are.
Tiger's Heart wrote:I could propose another reason for the 8 hours of sleep to replenish mana - magic is tied to the fade. Humans and Elves (for dwarves don't use mana nor have contact with the fade when they sleep / dream) must regain their mana reserve by contact with the fade for a reasonable duration. This occurs when they sleep and visit the fade in their dreams (even if they have no recollection of doing so).
You know, that is a pretty clever explanation - I'll have to remember this theory.

On a sidenote: Are dwarves truly "shut off" from the Fade? I was under the impression they just don't birth any mages, but that they still dream and thus visit the Fade like any non-mage human would. Or rather, that "dreaming" and "being in the Fade" are synonymous and you can't have one without the other. Unless you are a blood mage with lots of slaves to spare.
