I've been working lately on a tactical RPG (like Final Fantasy Tactics, but much simpler) and am in an extremely early phase of development. I recently put in a skeleton of a battle system whereby at the start of battle, all participants (several on each team) are placed on a special z level dedicated as a battle field. You can move via commands assigned through a menu, and the interface works to my satisfaction.

But there are drawbacks to this. Since maps are not dynamically allocated, I have to have enough layers reserved for the maximum number of players, and my system of assigning players to open battle fields is just asking for bugs. Since battles might take place in fields, forests, cave, or other environments, I have to prepare the field in advance by populating it with the right turfs.

So, I have been thinking about converting to a pure HUD form of battle. Any mobs taking part would be put into the null location for the duration of the fight. This system has drawbacks as well, since any object or animation added to the fight would have to be individually put into each mob's display.

Anyone have any thoughts on this? If you've done a tactical RPG, how did you manage this issue and do you wish you had done it differently? Are there performance risks associated with a HUD battle system?