I have heard of MageKnight but I think it was discontinued before I started plotting my dungeon game ideas. From what I saw of MK it looked like it was still very much a Team VS Team game like Heroclix. I want to create something where you are either solo or co-op (although maybe Deathmatch/Team games could be tried too).
One thing I'm doing differently in my game is creating "mooks" for the general baddies. Heroes will probably have a nice neat 10 hit points. Monsters will have around 3hp on average. Orcs or tough guys may have 4. Big monsters & bosses will have many hp but then they are for the party to take on as a team.
I mention Heroclix/MK a lot but I'm not using a click-base system. You get hp as you would with most adventure games and your special powers are useable anytime (although you can use them all up - I'm either implementing pips or cards to represent them).
I really just liked the simple stats in Heroclix - plus I thought the 2D6 attack rolls offered more varied in-game results than rolling a single D6 as you would in WHQ or many other games.
I'm struggling to think of a cool way to implement magic though. I love Warhammer's magic dice & dispel dice system so I may do a small-scale vesion of that.
Remember, sometimes you roll a one...
http://dungeon-gamer.blogspot.co.uk