Sense mob aggro by X

[carlosx]

if add soo many detection's ways, will also has to improved the ways to avoid confrontation as invisible sneak deodorize

[Jynx]

Some mobs aggro by sight - you can jump up and down behind them and they won't aggro.
Some mobs aggro by sound - you can walk around waving your arms in their face and they won't aggro.
Some mobs aggro by sight & sound - you can only walk behind them.

You got them all right aside from Sight/sound there are Truesound mobs that agro if you get too close (Front or back) but if your walking have a reduced agro range compared to if you are running.

Personally I prefered when monsters had better AI including mobs that would warn you, or search for you if you got too close.