I went through the player's handbook and compared all wizard spells of 1st to 5th level that had, "save or suck", like effects that could be used in combat. To understand if Fear's effects are unusual let's go through them level by level and look at how saving works. Spells for each level will be listed with more detailed information after. If I don't list more detailed info for a spell it's just your run of the mill save or suck.
Special Note: Concentration
Nearly all of the these spells use up a wizards concentration. The four exceptions are Color Spray (which only lasts one round), Grease, Sleep, and Blindness/Deafness. Since concentration is near-universal to save or suck I won't be mentioning it again in the comparison unless it's an unusually long case.
Level 1: Charm Person, Color Spray, Grease, Sleep, and Tasha's Hideous Laughter
Sleep and Colorspray are unique among all of the save or sucks in that they allow no save but are based off of the target's hitpoints. Since HP scales up so quickly with CR these are unlikely to be useful early in a mid level encounter so I'm going to ignore them for now.
Grease and Tasha's Hideous laughter both allow a save each turn to escape and failing that save is going to make it difficult to function in combat. These are prototypical 5e save or suck spells and this type is still common at higher levels.
Charm Person is the odd man out at this level. It is very limited; the creature must be a humanoid and they have advantage if you're already in combat with them. That said if they fail the save you have up to an hour to do anything except attack them.
Level 2: Blindness/Deafness, Crown of Madness, Hold Person, Phantasmal Killer, Ray of Enfeeblement, Suggestion, and Web
Most of these are standard save or suck, but Suggestion stands out. One wisdom save and then they are off for a nice picnic for 8 hours (assuming concentration). Limited because the monster has to understand you and your suggestion must be reasonable, also you can't attack so it'll likely still be around.
All the others are standard save or suck fare.
Level 3: Bestow Curse, Fear, Hypnotic Pattern, Major Image, Sleet Storm, Slow, Stinking Cloud
Bestow Curse is notable in that while they save every turn the effect doesn't end on a failure.
Hypnotic Pattern is an example of a common type of spell I'm going to call, "Save or Wait". You make a save and if you fail it you... wait around until the spell is over. This is a better than usual example in that the party can still interact with you however any attacks will give you another save. We'll see more of these later.
Fear stands out at this level as, assuming the target has somewhere to run and the wizard can follow, the creature may only get the one save. This has some significant downsides like the creature will be dashing away making it hard to keep up, positioning has to be right, and in combat with many creatures pursuing is likely to be difficult. However Fear still stands out as it is the only spell at this level that can only allow one save, disable a creature, and let the party continue attacking it directly.
Level 4: Banishment, Confusion, Control Water, Evard's Black Tentacles, Otiluke's Resilent Sphere, Phantasmal Killer, Polymorph
So many save or waits! Banishment, Resilent Sphere, and Polymorph all fit this category. Banishment can do worse if the creature is planar, and Polymorph can do worse depending on creativity and how your DM handles it.
The rest are just save or suck.
Level 5: Dominate Person, Hold Monster, Modify Memory, Telekinesis, Wall of Force, Wall of Stone
Modify Memory is much like Charm Person but with more horrifying implications. The same restrictions apply (advantage in combat, can't attack), but depending on what you can do with an altered memory this could be a, "Save or Ally".
Wall of Force is special in that it's the first, "No Save Just Wait". Like a DMV for monsters and you're the teller going to lunch. But it's nothing compared to....
Wall of Stone is something very special, the first save or die. It's conditional in that they need to be located somewhere you can trap them or it's just going to be a save or wait. If you can trap them though... dex save or be locked behind 6 inches of stone for all time, assuming the wizard keeps concentration for 10 minutes.
Conclusion: Fear is... actually unique
Looking through this list we see that Fear is the only spell (in levels 1 to 5) that only allows one save and lets you still wail away on the target. It's versatile in that it allows no extra advantage if used in combat, and it's not limited to any class of creature. It is situational though, if they can't run then they can resort to ranged attacks and still function. And if they can run you need a way to keep up with them. All that said, and looking at the other spells around at the mid levels, I'm convinced Fear's single save option is out of line with other spells at this level.
I discussed Fear with my DM and, after seeing this comparison, he agreed that its single-save possibilities were out of line with other spells at the midlevel. Going forward we're going to house-rule Fear to also allow a save when the target takes damage.