Metamorphic Transfer--What to Do?

Phantom Fungus doesn't seem like a problem to me. Sure, greater invisibility as long as you stay in the form is great... but you have to be a fungus!

I'd rather be a perfectly visible stone giant, or a Tiny (and thus easilly hidden) pseudodragon with three times the fungus's base speed as a fly speed!

What about adding this to the feat:

You cannot assume SU abilities that are constant and always active (ie. Quickness) nor can you use SU abilities that enable extraplanar movement (ie. Ethereal Jaunt).

The first to prevent the abusive abilities which if anyone can find a creature with SU regen or SU damage reduction/spell resistance would be almost on par with Quickness.

The second to prevent all the Ethereal Jaunting that is available for 4 different creatures.

The only thing this one doesnt prevent on my bolded ones is Enslave from the Aboleth.