You are correct, mobs that are not rooted and even if taunt lands they still will not turn on you. I find that this happens often enough for me to question how taunt works compared to my ability to tank on live.

when a mob is rooted, proximity becomes the only factor that determines aggro

Top hate +1 is not enough to make them turn though is it? I'm no expert so someone tell me I'm wrong, but I was under the impression that you need some %age more hate than whoever the mob is currently attacking before it will turn. That person still needs to take it easy after your taunt works so you can gain that lead required to turn the mob.

This is the main reason. +1 is not enough to get the hate back. Generally a weapon swing or weapon proc follows which is why the taunt seems to work. This is how it has worked on Live for as long as I have been warrior-ing. I am not certain on how much hate extra is needed to turn the attention, but I believe its fairly small.

Yeah I think it's only a few %. Can't remember where I read about it... Researched it at some point while trying to reduce my rate of ranger gates on raids.

I thought Taunt doesn't work on mobs above Level 50 in classic.

Never known Taunt to be level capped, but I have no evidence otherwise.
Logically, it wouldn't make sense to cap it.

When in doubt, let the over-casting wizard die.

It's how I learned to play a wiz on live. Was my first character. I learned QUICK that if you overnuke/nuke too early you're mincemeat. Also learned not to run around like a chicken with my head cut off.

Always waited until mobs hit a certain % to hit my first nuke. Then monitored fight. If it was smooth, I waited until the HP bar was 40% and started unloading. Monitoring the bar and gauging agro... If the fight wasn't going as smooth, and wait a few seconds and hit the mob again and then wait to unload.

I was never afk as a wiz. I root CCed and all that jazz. Was laughs and good times.

But did you use your stuns to interrupt casters? I've grouped now and then with wizards on p99 and I've yet to see even one of them interrupt a CompleteHeal cast unless the mob was low enough health to drop it with a nuke.