Hypnotism can be useful, sure, as long as you aren't running into the hit die limit. Since you've house ruled that, your example is outside the realm of discussion.
Umm, no? Using magic power attack keeps hypnotism useful even without my house rules. Plus like Krushnak said, there are often lower HD people around in variety of circumstances who can be affected with hypnotism even without magic power attack. Perhaps not in combat - but in other situations, such as dominating a servant of a noble manor to open the side door for the party to enter. Just because some spell is not useful in combat against 10 or 20 HD foes does not mean that it is not useful at all. It all depends on the circumstances. If the nature of the campaign mainly involves fighting 20 HD monsters, hypnotism won't be much of an use - but neither will Gather Information, unless you try to ask the monsters about their weak spots. Does that mean social skills are useless or broken? I don't think so.
Which curses have been useful, exactly? And how?
Greater Ill-fortune has spoiled the day (actually, months) for both NPCs and PCs when they have been on the receiving end. Gelid Bones is a curse and definetely useful. The curse that causes all wind around the target to die has had several strategic uses in the campaign. Foxing is a horrible, horrible curse for killing someone safely from afar. The same goes to Doom of the Doll.
It seems you've house ruled quite a lot in order to make the class playable. My original question was, "what are the tricks other players here use in order to make the class playable without breaking the rules?"
It is completely playable without "breaking the rules". Just use magic power attack to overcome HD limits and the like. Whether the sorcerer is capable of wearing armor or not is not a big deal. This is especially true as Scholar as a class is perfectly playable even without any spells at all. So are you talking about Scholar class or sorcerers? They are not always one and the same.
Seriously, I want to believe you, but you've provided no evidence to support that claim. That leaves me wondering how it can be possible.
Evidence? Should I provide recording of a gaming session or something? (I'd put a smiley here if I'd use them..) But seriously, I could think of a hundred places where unmodified spells used without effect of our house rules have saved the day. In last two sessions, casting Sorcerous Garden delayed pursuing horsemen several times with its overgrowth use. Without the spell, the group would have been forced in to a fight they could not have win - two or three times, if not more. Gelid Bones has paralyzed dozens of foes in combat that had been very hard to vanquish otherwise. Calm of the Adept has saved life of the caster from a very nasty stuff that would have fell on him otherwise. Domination and Suggestion, used in par with Conan rules (the victim has had HD under the limit) has given critical information or other help at various places. Visions has given the party information they had not received otherwise, together with Psychometry, as well as warning them of mortal dangers - so they've been able to prepare for them.
Raise Corpse has provided a servant, that has both set off traps in tombs, scared weak-willed opponents and drawn fire from the enemy - not to mention carrying, dragging and moving heavy stuff. Finally, Warding and Greater Warding has prevented sorcerous doom falling on the characters many times or provided cure for on-going effects. Incantation of Amalric Witchman once incapacitated a demon that would have otherwise been impossible to win. The War of Souls is not a spell, but it has proven to be a decisive factor in two critical combat encounters.
I could come up with more examples - especially if I started to take in to account spells that NPCs, both friendly and hostile have used - but there's a few. Note that those are only the ones found from the basic book. There are more useful spells, used succesfully, from other books. Scent of Rot and Fear (or something like that) has been a life-saver, for example.
I keep hearing this. That's why I asked for the tricks Sorcerer character players use to make the class playable without breaking the rules. I still haven't gotten an answer to that question.
Perhaps that's because there are thousands and thousands of things to do, depending on the situation at hand. Like I said, if the game is primarily only about endless combat, low-level sorcerer won't be able to do much usually. In other places, sorcery can be extremely useful. Divination and Nature magic are especially powerful, as they allow the caster to do things that are pretty much impossible, or at least very hard, to do by mundane means. Counterspells are very powerful for the same reason.
That's all fine and good, but you are telling me that to make the class playable, you have to igore the rules. You're agreeing with me.