There are no tricks, no cool approaches - a suboptimal party will suffer to an insane degree while an optimal one will also suffer, but less so. You can't summon a Mordenkainen's Sword to clear out all the illithids without breaking a sweat like in BG2, for example - the spell selection is very limited and there are way too many transformations that are freaking useless for the most part because their parameters are not balanced properly, but not really any actually interesting spells. And with how much combat there is, it became stale for me pretty quickly.
It seems, for whatever reason, the D&D folk were determined to make spells as underwhelming and boring and uninspiring as they possibly could. You don't even need to compare with BG. I did one sorc run in NWN and I was still able to have fun. It's like they took out the most fun spells, looked at the rest and went "now how do we make these ones even less fun?"
- Right, first we'll have a bunch of spells that increase one attribute score by 4 to fill up the level 2 slots, then make them aoe to fill up the level 6 slots, but don't forget to make these bonuses "enhancement", meaning that these spells become useless at around level 8 or so because by that point all characters already have a belt/headband that gives them +4/+6 enhancement to their core stat(s) anyway.
- Next, we have a spell that gives an ally a +2 morale bonus to a few things. Increase that bonus to +4 to make it a level 6 spell. Then make it aoe so we have a level 9 spell.
- Foresight is added by a mod to BG2 as an HLA and it's more or less worth a HLA slot. In Pathfinder? Useless. I find it baffling that they thought this spell is worth being a level 9 spells. In BG2 anything coming from level 9 has the potential to wreak havoc even in late game.
Like, seriously, what the hell happened? Like they seriously hated how fun spells are in BG/BG2 and made a point of not allowing players to have fun playing with spells anymore. Going through your available spell lists when you're playing level 18 clerics/mages is just heartbreakingly sad.
...and let´s not talk about how now every debuff spell, being pinned, enchanted, charmed, paralized, etc allows a SAVE EVERY TURN. Hey, I want to burn a level 6 spell to mass charm or cause mass fear for a huge 6 seconds, one entire turn, to the enemies, yes please. And if for some like phantom or weird they have to fail 2 saves, just because =D
and it goes worse from there. In D&D5e you have to use higher spell slots to buff all of your party, because even the classic party is made of 4 characters all our spells allow only 3 characters to be blessed, aid, enlighten, etc; by default so you have to use higher spell slots to buff them all. That if you do not want to use 50% of your offensive arsenal, like hold person or storm cloud because you lose concentration and lose your protections if you try to attack too. because hey, when I play a caster character what I want to do is not be allowed to cast spells just because.
I´m now used to this but... Really, I mean, really?