For years, I looked for a wave editor.
I never found one.

I tried to make my own but, coded using Haxe, it's not really usable and noone really care.

Recently,  I used Tiled to edit my Bubbler game's puzzle....so why not do the same to edit my waves ?

Et voilà :

I use 2 layers:
- tile layer let me set the tile of the sprite to launch
- object layer let me set any property I want on this sprite

Using a python script based on PyTiled-parser, I'm now able to transform this map to a array of wave item with

struct wave_item {
 unsigned char itemID;  //MSB = enemy type, LSB = item 
                        //if MSB != 0, item is dropped when enemy killed
                        //and 0 = no more item
 unsigned char pathID;  //path to use, 0 if linked to enemy type (ie most of the time?)
 short ypos;            //start at (x, ypos)
 short xDiff;           //xDiff between this item and the previous
};

I'm not sure pixel perfect , and not 8pixels rounded coordinates, are really needed but we don't really care, and it could be easily fixed, if a short or an int is not enough for xDiff