As mentioned, ToEE was a turn based, tactical combat focused D&D game - and actually featured some of the best combat of any D&D. Mobs and bosses fought using intelligent combat, traps, numbers, surprise and to the degree available then, positioning. They did NOT need hp bloat. Momma spider in EA has mid level support spiders, mass mini spider spawn ability, climbing ability to make use of stealth/surprise, poison attacks, multi attacks and so on. There is no reason to add an unnecessaryhp bloat - especially as that leads to further bloat down the line.
I can accept some bloat where goblins are concerned (as goblins can have classes and levels just like the player character) but even then, most goblins should be lvl 1 normal goblins, just as most humans townfolk would be level 1 human bakers, groundskeepers, scullery maids and so on. But 100+ hp spiders (unless they are handmaiderns of Loth or such specialized 'boss' material) do seem to be overboard, and leading to 300 hp tigers, 500 hp ogres, 2k hp hill giants and the like. As pointed out, a 15th level fighter could have close to the 184 hp Firkaag the red dragon possessed in BG2, but numbers and tactics were still needed to overcome all those delicious dragon offenses and defenses. Firkaag didn't need more hp than the total hp of your entire group to be a good opponent.
Yeah. Now that you mention Firkraag : he haste himself, stoneskin, has incredible ac and attack speed, incredible attack damage, a AoE that can one shot your weak party member, a buffet attack that knock out everyone around him and send your character rolling to the edge of the area. Not to mention his magic resist, backstab immunity, invisibility detection and a variety of spells.
About resilience : Stoneskin made it so he could take like ten hit, and ten hit with his armor was quite a lot. Unless you dispelled it of course.
So yeah, I agree, Firkraag didn't need more hp. he just needed resistance against almost anything you could do to him, and the ability to two shot almost any party member.
I dunno about the HP bloat thing. If Larian can get closer to BG2 , I'd say yes, anytime, any day. So maybe yeah, less HP bloat, more defensive ability like stoneskin and what not. But since the levels of the character are low, its not like they can use buff and defensive spell yet . After all, you started BG2 at lv 7/8. And baldurs gate 1 was like, much more deadly and random . One critical / magic missile basically could kill anyone, you or enemy , during the first level.
Also, the HP scaled pretty quickly in baldurs gate 1 , contrary to the second. In BG1, you earned like 6 to 14hp every level, ending in 120 HP Khalid at the end of the expansion (durlag tower).