>> Could you point those out?
Sure.
1) You said aliens don't use plasma grenades in 2.3.1 - they would (I'm fairly sure), but only sometimes. The AI isn't very good at using them, and as you noted, it does vary between versions, as AI code is tweaked, as plasma grenade spawning is rebalanced etc. They still don't use them much though
2) Morale system - it does apply to both sides, but it's quite rare to see a PHALANX solder panic, unless a lot of bad things happen to them in quick succession (ie get wounded, and see multiple soldiers / civilians killed or wounded in their LOS, death of comrades), and that has pretty much always been the case. Aliens tend to suffer the effects more, because typically when you kill one, several will see it, and aliens can typically tank more shots than a PHALANX soldier so they get the wounded penalties more often
3) Walls stop shots - Walls stop *some* shots. Several weapons (sniper rifle, bolter and coilgun, mainly) have a specific through_wall_damage rating, because you very much can shoot through walls. Some wall materials are stronger than others, of course, and shooting through a wall costs damage potential, but it is one of the humans few advantages (try UFO floors in particular... fun times). The alien plasma weapons don't shoot through walls, even if the AI doesn't know that
This, particularly, is an example of just having to *know* about it, I'm not sure there is anywhere within the game that makes it clear that capping things through walls can be a thing
There were a few other points, but they were to do with changes since the version you reviewed (strength / encumberance system, deprecation of the Heavy Weapons skill and max squad size, for instance), so not really relevant
For the LP, if you can get to grips with efficient use of smoke, and thoughwall shots when assaulting UFOs, you can save many PHALANX lives