And let the dice fall as they may

There is always GM interference in the fate of the players in an RPG.  The GM *could* drop an asteroid on the group at any given time and they need to actively intervene to avoid that circumstance... the question is, what sort of interference makes it more fun for everyone?

When I run monsters as the GM I try to play them according to their intelligence and view that as my challenge.  Sometimes the enemies are very coordinated and clever and will try to focus fire characters down and use other scary tactics but I am also perfectly happy to run boneheaded zombies that just zerg the closest thing no matter how foolish that might be.  I want the monsters to scare the players, to make them work for it, but I don't actually want to beat them.  To achieve this I don't particularly need a crunchy system and could be happy with something like Dungeon World which has combat resolution along the lines of 

Roll High:  You succeed.

Roll Medium:  You kinda succeed, but something goes wrong.  The GM makes it up!

Roll Low:  You fail.

I am fine running with this sort of system as it gives me the flexibility to amp up the challenge of a fight in the middle or tone it down by making things up in the ways I want.

On the other side of the screen as a player I want a tactical fight that lets me work as hard as possible to win.  I want hardcore crunch and I want the monsters to do their damndest to murder my ass while I do the same in return.  I definitely don't want any deus ex machina rescues nor 'make it up as you go along' fights.  What I crave is a scenario where I face a terrifying foe and I have to use all the resources at my disposal to defeat them.  Obviously the GM sets the initial fight conditions but once those are laid down I want the dice and my skill to determine if I live or die.  

I am happy to roleplay in combat to an extent - some characters are cowards, or foolhardy, or will try to defend a particular other character who is in danger even if that isn't optimal.  That can be a lot of fun and add interesting twists when other players freak out at poor strategic choices (right Naked Man?) and that sort of high drama in the middle of a life or death battle is the stuff of great memories and stories told for years afterward.

As a player I am not particularly satisfied by combat in crunch light systems like Dungeon World.  I would rather go full bore roleplaying and not bother with complicated dice chucking in that sort of system as it doesn't really grab me the same way.  When my strategic choices are inevitably lost in the vagaries of random GM decisions and random dicing I just don't feel the urge to put in the time and effort working the numbers.  Not that it is bad in principle necessarily, but it holds no appeal for me.

For me Heroes By Trade is ideally set up to play since it works very well with the idea that fights are predictable tactical problems the players can try to 'win'.  You don't have to play with an emphasis on tactics if you don't want it but it is certainly a big focus of the game rules.  As a GM it is about as good as any other game I think since I have fun running games in pretty much any system at all.  (Largely because I am going to hack them to pieces to suit the campaign and my mood anyway.)

When it comes to new players though I think the right balance is a game that provides clear answers to what happens and doesn't expect the GM to constantly come up with rulings on every roll.  Not everyone is up to that challenge and I believe that making an RPG that makes it easier to GM for people without strong improvisational talent is a really useful goal.  One of the things 4th edition DnD did right was make it straightforward to build appropriate fights and run them as tactical challenges.  I want to achieve much of the same thing in terms of making it easy on new GMs without all of the issues that plagued 4th ed.