Here's an interesting thing: you can mind leech their mind leech, use it to mind leech yours and thus mind leech theirs again for an infinite loop until the lower HP one dies (or theirs if they have equal HP) and it only costs you 2 Aether.
I don't see this as a problem because it's only one situation and it's sheer luck as to which player loses out this way, it's just a strange and gimmicky interaction that I find fun.