[Khumak]

*Warning, some spoilers included*

I've found all the battles in tactics quite doable. The caveat being when you do them... The boss fights I do by the end of chapter 3 are Illych, Maevar, Torgal, and Bohdi. I save all the rest for chapter 6. Unfortunately some of the fights are basically impossible without foreknowledge.

Improved Irenicus is extremely cheesy and annoying for it's placement in the opening dungeon. If you make a custom party it's doable with zero cheese. All you need is enchanted weapon and magic missile. If you're playing with the default party and your PC is not a mage it can be very frustrating. The real threat is the cleric. Interrupting him is an absolute must.

Bohdi is extremely hard if you do her in chapter 3 instead of chapter 6. Doable but very hard especially considering you have to go through her to advance the story if you're playing a good party. Some of the other stuff like the druid grove are also best left for chapter 6.

Torgal can be really nasty if you send a fighter type in to go toe to toe with him but he's quite doable with a level 10 or 11 party. However badass you think your main tank is at that point, Torgal is badder... I use his see invis against him by pulling him solo with a thief and fighting all his thugs after he's dead. Buff up, lay a few traps, send the thief in to pull him, dispell him, slow him, nail him with ranged weapons and spells while you pull him through the traps, then finish him off with melee.

Maevar is easy especially if you pick pocket everything before you go down for the fight.

I'd say the improved mage mod is by far the most annoying overall. I wish it had an option that only goes all out on the boss fights. As is, I find it too bothersome to constantly have to dispell all of the contingencies that all the trash mages bring up so I kill most mages with my fighter types using plain old non magical weapons and no spells. Sometimes they still get a spell off but usually not. With non magic weapons you just have to spend about a round burning through stone skin and then they're dead. It would be even more irritating for most of the game if the mages used Absolute immunity instead of PFMW because then you'd HAVE to dispel everything unless everyone was packing +5 weapons.

The Sahaugin city can be rather frustrating as well if you don't have either some high level mages or some high level thieves. This is especially true if you skipped most of the chapter 3 stuff and went to go save Imoen asap.