And in 5e? The focus always seems to be on fireball.
I think this is the case on newbies, but experienced Wizards don't overuse fireball. Tashas summo spells or controls are the bread and butter 3rd level spells in 5E for experienced wizards
Hypnotic Pattern - now that's big. It will take a fight that's well above the groups paygrade and turn it into a winnable fight. As levels get higher, the wall spells beat cone of cold any day of the week, when used effectively.
Hypnotic pattern is actually overated. Most experienced controllers go with Fear as it is the heaviest hitter at level 3. Another good control spell is actually Summon Fey. It is not as powerful as the others instantaneously, but the round-over-round bonus action charm along with positioning another ally on the battlefield really puts out quite a bit of control.
There are two big problems and one smaller problem with Hypnotic pattern which make it tricky:
1. Once you damage someone he is no longer charmed. This means unless you can 1-shot downed enemies they are going to get back in the fight with first damage. This also makes AOEs difficult to field if you have a mix of charmed enemies and enemies that saved.
2. The wake up ability means intelligent enemies who have seen this spell or know what it is are going to wake their friends. Since they wake up immediately, in only takes one of them to make the save and all of them will be back in the fight the next round. This results in a chain reaction - you get 9 out of 10 guys to fail - the guy that is not charmed uses his action to shake a guy out of it, that guy uses his action, that guy uses his action ..... in the end it ends up typically being like 1 lost action for those that fail Some DMs rule that you lose a turn after you wake up, but that is not RAW, RAW the wake up mechanic puts a significant achilles heal into the spell.
3. A lot of enemies have advantage on saves against charmed.
Fear on the other hand will almost always end a fight for those that fail.
If they are in a dead end like a room with only one entrance they can't do anything and they can't save again. The wizard can hang back in the doorway and throw daggers at them until they are all dead while the fighter brews a pot of tea and there is nothing they can do about it.
If they can flee then they do flee, but they can't save again until they are out of sight at the end of their turn. Since they used dash this means they are 2 moves out of the fight minimum, which means a minimum of 2 entire turns lost (one fleeing and one dashing back), while also causing and taking damage from AOOs and that 2 turn minimum is if they can break LOS on the first turm and also make their save. If they can't break LOS or fail the save again it is even longer and every turn they take is another extra turn to make it back ..... flee for 2 turns and they are out of the battle for 4.
We had one game where all 4 enemies failed their saves and the party just dashed after them and used AOOs on them until they were all dead. The rogue got in some normal attacks too since he could dash as a bonus action.
People will point out that fleeing enemies might not be a good thing, and I guess that might be situationally true but strictly in terms of combat mechanics Fear beats HP by quite a bit.