So in leveling to 13, I've noticed that there simply are no aggro mechanics. Is this some low-level thing that existed in EQ which I have no memory of? Like threat literally is not a thing so far. Mobs attack whoever is closest to them (no, they're not rooted) and taking aggro from another character isn't possible at all. I've had adds that were only on the tank by proximity aggro and I could mez them twice and the tank still has aggro when the mez wears off. Like there undeniably is no aggro whatsoever thus far. My enchanter can pull with a stun nuke and one melee swing from my paladin grabs aggro. Does this suddenly change later on? In fact, I was able to pull two mobs with my enchanter, walk my tank up to them as they arrived and hitting one while moving away with the enchanter, which caused both mobs to turn on the tank (who hadn't even so much as targeted the other one yet) and then I was able to tash+nuke the add without getting aggro. The tank had generated 0 threat on that mob. I do not remember this being the case even at low levels back in the day, but it has been so many years that maybe I forgot. It just feels weird and inappropriate. I don't know of any low-level easymode aggro nullification feature.
I invite you to read Torven's analysis of hate list logic and spell hate values. Also maybe skim through this topic. TL;DR: Hate logic at lower levels is still a work in progress but at higher levels is probably the most accurate an emu has ever seen.
The closest hate adder is like 75 or something. At low levels, closest is going to get aggro almost always. Initial aggro will always be biased from this at lower levels. Shouldn't be too bad a higher levels tho.
As an anecdote, I noticed similar reactions when I leveled my warrior and friends (Dru/Enc), Burly. My recommendation is to use this lower level agro mechanic to your advantage and level up your tank's multiple weapon and shield skills. Raise up all those one and two hand skills during the days of easy agro, because it may be harder to later.
I'll second Lenas' advice to check out Torven's analysis of hate mechanics. It's a fascinating read. A couple of the relevant highlights are that there's a flat 100 hate bonus (or maybe it got adjusted down to 75? Something in this range!) for being in close proximity to a mob, and that most of what we think of as "aggro" effects (snare, stun, etc) have a scaling hate value equal to the target NPC's hitpoints divided by 15, up to a cap of 1200. That means that at extremely low levels, the 100-hate proximity bonus is going to be hard to overcome with a lot of other kinds of aggro (especially if you tack on other bonuses, like the two Lenas mentions above). Some TAKP players - myself included, actually - don't think that this "feels" accurate to their experience, although it may be an accurate reflection of the current state of EQLive. Once you start fighting mobs with a couple of thousand hit points, however, the system becomes much more recognizable. At high levels, there may yet be a few unanswered questions and imperfect estimations (how much hate should disease counters generate, for example? there's no way to get a definitive answer, since it's been changed on EQLive), but by and large, the system feels dead accurate to most people's experience of the game on Al'Kabor.
That is classic behavior. The amount of hate required to pull off the person you 'trained' is questionable, but running mobs over people and getting them stuck on them is very classic. (again I refer you to http://www.notaddicted.com/fansythefamous.php for a good example) It's not a work in progress; it's how Live is currently. There is no way to know how old EQ was different short of AK's source getting leaked, so there is no way to improve on it further, otherwise I would be.