Definitely worth a try! Sounds not too hard to implement, too.
However, the trick will be to make editing/ handling these indices conveniently.
- What if you like to raise the index by, say, 1 for the topmost 15 layers?
- Do new layers automatically get a continuous index, or is it all left to the user?
- What happens when object indices are the same? Newer created object are drawn on top?
- What happens if layers share the same index? I guess what happens now - higher up layers are drawn in top.
- The MicroStation way of multiplying the layer index by 1000 (or something) and adding the object index sounds a bit hacky. Are there maybe even 2 independent indices, one for objects, one for layers, where layer index always takes precedence?
- Layout details should definitely be part of draw order sorting! If a detail sits on a higher layer than another detail, everything inside it should be drawn on top of the other, no matter what the indices inside are.
- Any changes needed to the old bringtofront/sendtoback commands then?