I've seen you mention this before. Can you say a bit more about the details?
The nearest comparison I can think of from my own RPGing experience - but the two systems I'm comparing are much further apart - is melee in RQ vs melee in RM...
Is this anything like the sort of point that you're making?
Sounds very similar, yes. Of course, the "culture shock" is not confined to metagaming, necessarily. In AE, the magister is using a spell system which is practically "shifted out of phase" compared to a 3E wizard. Spells can be diminished or heightened to change their level. Templates can be applied with considerable effects. The feat choices provide access to interesting cross sections of spells, and other such choices. By default, the magister only has proficiency with a staff--no other weapons. And then the bigger, more obvious, change, that all spell casting in AE is a hyrbid of the 3E wizard/sorcerer distinction, with spells "readied" from a larger list each day, but "slots" used for casting picking from the readied list and not commited until then. And a caster can combine and break slots as needed to get more lower level spells or a few higher level ones. In this way, it is a spell point system with sharp limits. Then you have niche things, like situational but more effective counter-spelling options than 3E.
So there are some almost metagaming/build choice in how to set up the cross-section of spells most efficiently--and related, party syngery thoughts for players that want to maximize their access to magic which can be done in character or out. But tactically (in character or out, your choice) there are lots of meaningful decisions that arise every round, and not just in combat. Is the equivalent of "fireball" now the best course, or split that slot up and get multiple, smaller balls of fire over a few rounds? Is one bigger divinition or object lore spell the best way, or several lower ones to get more questions?
Then when you get a good handle on that, you realize that the "akashic" character next to you is fully capable of doing this weird cross section of things that might be described as the backup melee role of the cleric combined with a skill monkey slice of the rogue and some of the utility abilities that the wizard would normally do. And with a few exceptions, most characters in your party are like that.
It also reminds me of another post of yours I read today or yesterday - I can't remember on which thread - which talked about 4 of 5 things circling the 5th, and suggested for this to work the 5th thing may itself have to be different, in new and perhaps unexpected ways, from all the other 4.
Am I right in thinking that this hit point reconceptualisation/redesign would be an example of that?
Yes. Most of the solid things, and more than a few of the goofy things, that were done with hit points in each version, were done for a reason. Each reason is a point on the grid that pulls the center somewhere. A lot of those points might be outside the boundaries if you could draw clear ones around the center, but the outside points still matter even so.