I can't say for sure, since I don't know the specifics of the DOS engine, but it may be that it effectively only keeps track of character (x,y) positions on a grid that we can't see. Clearly the maps can allow elevation (z) for terrain elements, but it may be that for characters all we have is their effective position on the underlying grid - and they are rendered in 3D at an offset above this terrain height (which involves a lot of work too). So if the engine is written like this, then it can't easily keep track of more than simple z-offsets from the terrain for a grid location (for rendering the character).
Even a levitate spell effect, which should just be +- z offset at a grid location, would need some fiddling with engine code, since it is likely that higher level scripting systems used for animation/pathing of characters (as used by level designers/artists) are written along the lines of 'move Character(c) from (x1,y1) to (x2,y2)'. Adding a 'z' to this (And keeping track of it) would require a lot of extra work and possibly worrying about solving 3D pathing. Proper flight requries a full 3D space - at the moment it seems like they are using the 'hover' abilty in DOS (avoid terrain effects), so not actual flight. I am not sure they can fix this without a lot of additional coding, too much effort for 1 (or 2) spells. Sadly. Of course, this is speculation - maybe they have refined the DOS engine to better handle z and we'll see more later.
Hmm, ok, that makes sense. Although I do think there are parts when you can go over or under a bridge for example. How would you keep track of that (since there are two viable positions with these coordinates?)
The simple solution would be:
introduce a status called "flying/ levitating". When casting the fly spell, you can spend 10ft of your movement to use the "fly up" action. This action gives you the status "flying". As long as the status is active, you are treated like you are 10ft over the normal position. (basically your model is changed so it is 10ft in the air). So like hover, but higher up. I guess that makes it harder with low ceilings/ buildings/ caves...?
So basically, if that is the case, just give us binary options. Either 10ft in the air or on the ground as base positions. Could that be implemented?
Thank you for the explanation btw, that makes more sense
