Stoneaxe:
Of course, everyone's situation is different and nobody can or should tell them what they should do. I can only say what I would do in your situation and absent any more specific information and advice from doctors.
If your tumor is largely confined to your IAC and you've already lost hearing on that side, then your greatest risk with watching and waiting would be to your balance system. From what I've read, balance is usually most affected when an AN is small. That's because, after the AN has grown sufficiently to severely damage the vestibular system, the other (good) side largely takes over and the brain somewhat ignores the absence of signals from the damaged side. (This is called "compensation.") Or at least that's what some literature I've read asserts.
That said, further degradation of sense of balance is your most likely risk. The facial nerve is much more resilient than the sensory nerves, such as the hearing and balance nerves, so while it's possible you could suffer the onset of hemiparesis, it's less likely than having your balance worsen. Once the AN grows into the CPA (cerrebelopontine angle) and approaches the brainstem, other cranial nerves such as the trigeminal nerve also become at risk for damage.
If it were me, and I must stress again that I'm only talking about myself, I'd watch and wait til either the tumor got a lot bigger or I started noticing an increase in symptoms. No treatment is without considerable risk, as you well know.
The problem is that this is all a big guessing game. I'm currently watching and waiting over a possible second tumor in my hypoglossal canal. We can only place our best bet and then let the chips fall where they may.
Sincerely,
Tumbleweed