Bards are fine. I've never understood people who think they are overpowered in IWD1 or 2, even with their songs. OK, war chant of sith gives you a bit of regen. Who cares? 2 HP a round is almost nothing in any situation where you would actually die, it's basically only there to save you needing to manually heal or rest during an easy dungeon. Even with the IWD1 EE Skald song its debatable whether its better than another actual combat character. Bards are best as a secondary nuker since their boosted level makes low level spells like Skull Trap slightly stronger. I think IWD2 bards are just much worse wizards?
Sorcerer in IWD1 EE is definitely 100% cheesy. It's fun, but the game isn't balanced for it. Spell scrolls are restricted in IWD1. In fact I think the EE might have added more scrolls for each spell and made the game easier this way, don't see many people complaining about this though. In original IWD1 you basically ran 1 wizard max, 2 wizards basically couldn't get enough spell scrolls to keep pace with their leveling. In IWD1EE you can run 2-3 sorcerers if you want and they'll get access to spells sooner than you should be able to, including basically game breaking spells from BG2 that the EE devs only put scrolls in on the last fight of the game before Ischaracht or however you spell her name, which ends the whole expansion. Which was good of Beamdog, you're not supposed to use those spells to utterly break half the fights in the game. But sorcerer can.
Anyway my general powergaming faceroll party for IWD1 is something like:
Fighter/Cleric dwarf
Berserker->cleric (if its IWD1 non-EE just go with another dwarf multi)
Ranger/Cleric half elf (if its IWD1 EE make sure you edit the config to let you use full druid spells)
Fighter/Mage/Thief elf
Bard (Skald if EE)
Wizard (sorcerer optional if you play EE, like I said they are OP)
Only downside is that 3 out of 4 melee characters are clerics so your weapon choice for them is pretty limited. But that's also what makes them powerful. F/M/T gets the frontline/defensive scrolls, wizard and bard share the rest with the bard specializing in low level nuking.
For IWD2, balance can be a bit weird. Fighters actually suck because there's so few useful feats, you basically only take fighter 4 to get weapon specialization and even that is dubious. Frontliners should all be Barbarian or Ranger or Paladin. And as is often the case in 3e taking 1 level of monk to play an unarmored character getting Wis to AC is often a good idea (though a lot less than in normal 3rd ed since you don't have many stat boosts).
- Human Illusionist: Illusion seemed like the best deal, IIRC it only prohibits necromancy spells? I expect on HoF monsters would save against those anyway. Single class because I want to cast those powerful spells early.
Skull Trap and Horrid Wilting. Also I don't think saves are boosted all that much in HoF. If you explicitly go out of your way to nerf enemy saves with stuff like Greater Malison/Prayer/spells that apply a save penalty, you'll succeed a decent amount of the time. Or just spam 10 webs on the same spot before luring enemy in.