I agree with what Ardanis wrote (years ago) in the other thread about Dimension Door being changed to a L5 spell which gives the user many innate DD or infinite DD for a duration. The Daeveron battle is very iconic, and it would be cool to do battle in the same way. Kind of like an inverse Teleportation Field with some tangential mobility uses.
I'm still not sold of Dispelling Screen. Originally, the formulae in BG2 was something like this:
Spells which removed protections against damage (Breach, Pierce, etc.)
Spells which removed protections against spells themselves (Khelbens, Spell Thrust, etc.)
Spell which removed everything. Dispel removed everything good and bad from friend and foe. Remove Magic removed only against foes at a chance for failure.
That was a good dynamic, with the exception of Remove Magic. It should have been a much higher level spell. Dispel Magic was a double edged sword that could still fail in its own right. Spell Shield is desirable because it works against a broad selection of spells with a narrow, if important, purpose. Dispelling Screen does the same thing, but against one spell. Not worthy. Much better to roll it into Spell Shield as it is already very situational and has opportunity costs of its own.
I did see how a few of the protections that Spell Immunity afforded have been rolled much more sensibly into other spells. There are plenty of gaps though. Most notably Necromancy. It would be really nice to have a 2E adaptation of Shadow Shield.
Regarding Hakeshars, they are a slightly better version of the Nishruu. Between the two of them, it was the only one worth casting IMO. If one has to go, it should be Nishruu. Not a major grievance either way though.
Finally, without Spell Trap being...a trap for spells, it's kind of pointless. It's just the ULTRA version of Greater Spell Deflection. That's not very interesting. If SCS AI won't cast against someone with Spell Trap active, that's more a fault with the AI than the spell. Not every spellcaster is a genius arcanist. Innate casters, divine casters, monsters with spell-like abilities, and even most arcane casters without access to Level 8 or 9 spells shouldn't even recognize it--at least not initially. With Project Image and Simulacra (item abuse) being fixed, anyone who can still find a way to abuse Spell Trap is going to break BG2 anyway. If you're going to fundamentally change the spell, just make it like an end-all-be-all Globe of Invulnerability for all spell levels--even HLA. Otherwise I'd leave it alone. It's part of what made the game good.