Got to play a bit with Intrinsic tonight for a while, was a lot of fun.
Just a tidbit on monster aggro - There is NO hard evidence for this currently, meaning none of the MH diehards have ever figured this out apparently. Some thought there was an aggro meter but that was debunked. After that it was assumed random, which is very well could be. From my experience it seems like it chooses people 1 by 1 and goes in a certain order until the monster or a person changes areas. I usually avoid attacks online by knowing that I'm usually going to be attacked every 4th attack. Sometimes the monster could do a pbaoe when I'm farther away, but then it will switch to the next target as if it already attacked me. I think this system holds truer than a 'random aggro' system. Sometimes I will admit it seems random, but when you play offline with just cha-cha, you see monsters go back and forth between you ALL the time (unless Cha dies, which is often).
Ex: Players 1, 2, 3, 4 fight a Jaggi. Player 1 enters a zone and gets with an 'aggro range' (I would assume the distance at which he spots you or the exclamation point goes up), then player 2, 3, and last 4. Jaggi will, for the majority of the time in the same zone and as long as no one leaves, will attack 1, 2, 3, 4 pretty much in order. Now it might do a shitty attack for one person and not look like it even attacked them, but from my experience it will move to the next target.
I have no evidence for this, but I'm pretty damn good at knowing when a monster is going to attack me so it has done me well so far. Especially if you were just attacked, as long as the attack isn't a chain/combo of some sort, you should be safe to use pots/whetstones unless the next person being attacked is right by you.
If any of you see this differently, throw your opinion out there. I'm sure there might be some varying factors.