The game was originally designed to allow the dragon form to attack ground opponents, but it required too much memory and had too much of a frame rate hit; see Lar's post in the topic
Design ideas for Divinity 3 (mostly for Larian).
If you are using a lot of healing potions, try adjusting your strategy (use the creature, etc), check for equipment upgrades or try a different area first.
With your battle tower runners fully upgraded, you shouldn't have any problems getting gold or potions. Send the herb runner for ginseng (or whatever else you need for the strongest healing potion you can make) and the other two for malachite ore and diamonds to sell; as soon as they leave the tower just teleport out and then back and they will have returned (usually successfully).