Actually, I want to use the same underlying principles to insure the mechanics are sound, but I don't want it to feel like a sport at all. I've delved into several archaic forms of football for that, but I'm also a hockey fan.

Do you want abstract player controls, e.g. assigning players and zones as targets instead of explicit movement orders?

Precisely. Aside from one player at a time, all other allies will be answering to AIs which is based on their role. That role is defined by you, from a list of roles, and none are necessary/required.

What skills differentiate strong and weak players?

By player, do you mean the person behind the screen, or the actual players (units)?

Skilled players (person) will have different unit compositions, defining their overal strategy based on the cards they are dealt (figuratively). Since not all players (units) are created equal, and that the player will be able to maximize the use of certain talents, their ability to determine what will "work" best with their team will make them better players.

Also, since they'll always control one of these players at all times, they actual efficiency with the game itself will help the team overall.

As far as players (units) are concerned, they'll all have various talents in different quantities. Some will be useful because of their speed, others because of their toughness, etc. I don't want to go into the very low-level details, especially before its even designed, but there will be many stats with many uses. Part of the game's appeal will be to determine how to use a player (units)'s strengths and weaknesses and define what role they should use (and there will be more than one viable option). Sometimes, a player will even be assigned a role that really doesn't fit their skillset, just because the TEAM critically needs such role. While the unit will underperform, it will at least fill a much needed goal.

For example, a team of agile and fast people could all go archers in a medieval fight, but if someone takes them headon, they'll all die. It might make sense to armor up one of the archer and give him sword and shield instead, so that he can soak up some of the damage. The same will apply to the game logic here, as each role will come with a different AI, and you're likely to want to cover some zones none of your unit is suited for...

Did you try existing football board games and computer games?

Yes and yes. Unfortunately, I want to play the realtime aspect here to make it more like the NHL feel (which bloodbowl doesn't achieve) and most computer games, aside from Madden, didn't help much in that regard. As I said though, NHL gave me the overall feeling I want to achieve, and now, I want to move away from Sports. If you have a game in mind that has the same underlying principles but isn't themed with sport, I'm all ears (in fact, my original post asked for that precisely).

What if you come up with a more combat based sport like pro bending in the new avatar show? (The legend of Korra)

It's always going to be difficult to have a situation that doesn't have very specific rules to be played out like a sport.

Well, my initial approach (and I'm finding this difficult) was to play the mcguffin card. For example, make the ball a "bomb" that you need to place in the opponent's base, knowing that the opposition can capture the bomb and nuke your own base. Of course, that feels awfully inorganic and forced, but I pursued this idea for a while, implementing a darkstone approach and similar concepts. It does feel like this is the kind of abstract thing that's better left unexplained.

While I'm ok with the game feeling a bit like a sport, I don't want to advertise it as such. First, I want to make the rules simple. A wall-enclosed area where you can check opponents against the walls is all I need. That said, limitation of warriors on the battleground will feel artificial, but I'm assuming people might be forgiving if its done right?

Second, I need to figure a reason for players to spread out. It would be boring if a team of rock-solid warriors could just form a big bioball of players around the ballcarrier and make their way accross the battlefield to score. This reason need to spur strategies.

Maybe I'm alone in this, but a secret guilty pleasure of mine was Blitzball in Final Fantasy X.

Very simple rules, a bit like handball underwater. Enclosed area, RPG "combat" throws and defence. Missing a bit of tactic, but I liked it.

I only ever played FF at a short lived friend's house, but we all loved Blitzball.

Maybe I'm alone in this, but a secret guilty pleasure of mine was Blitzball in Final Fantasy X.

Very simple rules, a bit like handball underwater. Enclosed area, RPG "combat" throws and defence. Missing a bit of tactic, but I liked it.

Interesting, I have absolutely no recollection of that despite beating FFX...

I'll youtube-it and see. Thanks for the heads up!

Unfortunately, this is turn-based. This drastically differs from what I'm trying to achieve here.

The real challenge I'm facing and dealing with a lot of AIs and how to make it manageable for the player. Being turn-based removes this obstacle somehow as it allows you to pace the game accordingly and individually control characters if needed (such as in Bloodbowl) whereas NHL and MADDEN's innovation comes from real-time management of all of the players and somehow bringing them together towards a common goal through different player-defined strategies (either through line changes, actual strategies/plans or just picking the right players and player roles for the job).

Thanks regardless!