Don't be scared, adb is your friend.
"A common mistake people make when trying to design something completely fool proof, is to underestimate the ingenuity of a complete fool."
As for ICS, yes it's taking a long time - but it even took a long time for the GNex to be updated to a modern ICS version (4.0.2 was an entire API level behind). I'd rather it take a long time, than be released before it is ready. I'll reserve being pissed for the launch, if it has more issues than the current GB OS, then I will be pissed.
Well what substantial issues does the gb os have in the first place? I barely noticed any aside from a once in a blue moon large drain on my battery and while annoying its very rare for it to happen.