Then allow me to freshify this discussion.
iChun has balanced Morph by increasing hunger use and making some mobs slower in certain environments. To be honest, that's the best "balance" you're going to get. Adding anything else is just going to nerf the fun of the mod. Now, before you start objecting to this, allow me to explain.
Most people have suggested changing the transformations so that you can't place blocks, use items, wear armor, etc. etc... This is an awful idea because it's just going to add the following steps.
- Morph into bat.
- Fly where needed.
- Morph back.
- Use items as needed.
- Repeat indefinitely.
This is just utterly tedious and in no way contributes to the mod. People still get flight out of it and can still use blocks and items once they morph out of the creature they were. It's like having a crafting table outside your house so you have to walk and back in to craft an item making crafting even more tedious. This doesn't add any kind of goal to work towards, it doesn't make the experience more fun, it just increases the amount of wasted time when morphing from creature to creature.
Another idea was to add some kind of ritual to allow access to the Morph ability. This is a much less terrible idea, but unless you like Portal Gun's
Hard Mode Recipe, which would most likely be the type of thing iChun would add, this isn't a fantastic idea. Also consider that Morph has no kind of tech tree to ascend. MPSA, Thaumcraft 4, Indusctrialcraft, and most other mods that add a type of flight, add some kind of tech tree. If you doubt the MPSA part, hook it up with Thermal Expansion and you'll understand.
The next step would obviously just to kill a whole bunch of the mobs you wish to morph to! Doesn't that sound great? I would really like to see someone enjoy finding and killing 100 or so bats. It "balances" your mod well, but who is really going to use that? People will just use Soul Shards to create a spawner to farm bats or whatever mob they want. Again, another way to add tedium to Morph.
You could make it so that Morph creatures have varying inventories. The smaller the creature the less it has, but then who would ever use those creatures? Who would use a bat that would have just a hotbar or a single line of inventory space? You'd just make the bat a useless option in the grand scheme of things.
Attempting to "balance" Morph isn't going to do much for it. You're not going to add anything more than tedium. There are plenty of mods that add flight and have the proper tech tree to give it a balanced feel. Therefore, adding an option to simply disable the flight from bats would honestly be the best option. I seriously cannot imagine any way that making Morph flight balanced that doesn't making it boring, tedious, and/or useless.