To add some fire to the discussion (which is quite interesting and reflects many of the discussions we had in-house) - how would your combat system look like if you could also fly ? Not that I'm saying you can fly in our next RPG, but suppose you could. You'd have to deal with things like air to air & air to ground, preferably with the same system in order not to confuse your players.

Well what exactly do you mean with "if you can fly".
With wings or on a dragon or another creature ? (or just superman style ? It's a bird! It's a plane! It's Larians next RPG!!)
Or maybe we could just after a certain time transform into a big cool looking evolved form of ourselves. (for a while, and offcourse be able to fly)
I guess we will have wings if that is the case.
There was this mmo"rpg" I used to play called muonline, after lvl 180 you were able to "wear" wings. It made your char look so cool and you could move alot faster.

Not really knowing how exactly you would make them fly, I'd say turn based combat has to be the easiest way to keep the same system for air to air and air to ground.
(different skills but the way to activate them remains the same)
But if we were able to have wings this opens tons of possibilities.(it might be abit weird though)
Well please let us know what exactly you mean with "if you could also fly".
Because imo thats very important to really be able to think about the combat system.

For an active combat system maybe your typical wasd keys to move and use another button (left shift preferably) to change the use of the mouse in fly mode/target mode.
But I guess I would still go for a Gothic 3 meets guildwars kinda combatsystem.
where the more close combat fighting options are enabled by using combos (preferably customizable so some people could just use the numeric or function keys)
and NO autoaim/autotarget system. (with maybe the exception of a few skills). So fly by and hit or grab as we get close.
The range combat really depends on what kind off skill you are using.
I want to aim with a bow myself or shoot a fireball in a certain direction rather than autotargetting it.
Some special skills/spells (curses for example or immolate or whatever) still have to autotarget your enemy. (since being able to "miss" a curse sounds abit silly to me).

Nah no turnbased...I'll think of a good way, cant think of any atm...

should i think about the transform into dragon flying, riding on a flying creature or both?