this game is not like other games in that you can't heal during battle here. with each hit, you must decide if it's worth attacking again, or if you should run (you have to think a move ahead, because you have to withstand one more hit when you run).
and for mages, mana is always a concern. there's mana-draining monsters, that are even harder to kill because you'll likely run out of mana til you lvl-up a few times and get closer to their lvl. there are ways to get mana faster... if you invest points in iq in early lvl's rather than later. but it all depends on how you develop your mage.
as for losing silvers upon death... it encourages something slightly realistic - don't die! or, as another option, don't carry silvers on you when you fight. and you don't lose 75% i'm pretty sure. if i've noticed correctly, it's a random amount between 33% and 67%. either way, you can avoid losing silvers if you know what you're doing (running instead of dying, or not carrying any when you fight).
--jason