Arcane Ward - 6; starts off as pretty useful, has less use as time goes on. Still, extra hp as a buffer is always good. Don't really think much of it outside combat, though.
Minor Conjuration - 9. Surprisingly useful. Forgot a ladder or a 9 foot pole? Need alchemist fire or acid to get through a lock? Oil for a door rusted shut? You always have the necessary tools for the situation at hand. People complain about flying or teleports ruining adventures. I've seen creative players bypass more dungeon challenges trivally with this ability than any other. Much like improved minor illusion, I consider this to be a game changer, in that it literally changes the way players approach the game.
Portent - 7. Being able to replace a bad roll is pretty good. While needing to make the call to use them early on is less handy, but it lets you plan ahead a bit, making this a good defensive ability or a good buff for the party, depending on the day's rolls. Luck manipulation is always handy in so many ways. I'm rating this lower than usual, though, because of two reasons. First is that I've seen far too many average rolls, which is less handy than something on the extremes. Secondly, because it needs to be before a roll, you have to be on the ball with watching combat, and you'll always wonder if it was necessary to use the die.
Hypnotic Gaze - 1. I want to like this. I really do. But spending up your action to just freeze a monster in place, and not being able to move, and to maintain your action? Its a variation of hold-monster, I suppose, except it takes up all your actions, and can't be relied on in most places. Its a desperation move in combat, and I can't see many situations outside of combat, given the obviously magical nature ofthe charm. Alter Memories is practically REQUIRED to make this worthwhile, and that's a level 14 ability.
Sculpt Spells - 10. You can use explody spells without worrying about injuring your companions. This is awesome, in that you can fight in the middle of a town and not burn it down. You can also brute force things like doors or bolders and not harm your environment. Its lets you treat your spells like a sledgehammer without friendly fire or collateral damage. That's amazing.
Improved Minor Illusion - 10. Illusion spells are the bomb. This is great for distractions, avoiding combat, etc. Less handy if you have a game that encourages just running up and smacking enemies all the time, but any situation with a need for subtlety? This is your ability. Its something I've seen arcane tricksters multiclass into wizard specifically for. Its very good and can be used for a wide scope of situations, especially preparing ambushes or any other kinds of distractions. Much like minor conjuration, I consider this to be a game changer, in that it literally changes the way players and their characters act.
Grim Harvest - 3. while hp is always nice, especially at low levels, its not something that really helps the necromancer, who's really just starting out other than minor survivability. This is rated less than Arcane Ward not only because of the less hp recovered, but the lack of necromancy attack spells until level 5+ outside a cantrip, which doesn't even apply to this ability.
Minor Alchemy - 1. Not very handy except in niche situations. I see it primarily used trying to break down something by making it weaker. Ovreall, its outshone by minor conjuration.
Bladesong - 10 to 5. 10 because its necessary for a magic swordsman to do their thing. 5 because its less useful as a devoted spellcaster than some make it out to be, given the wealth of defensive magics available to a wizard. Might be good in some situations, but not often in my experience. Just kind of there, and its really only good for combat. It can't be reactive like a ward either, and its only twice per rest, so it runs out of steam in time, meaning you have to bank it and not splurge on a difficult walkway or dungeon part, etc.
So, there you go. In case you couldn't tell, I put a lot of stock in the abilty to use these abilities out of combat as well as inside it. Combat is easy, but I find that tactics matter far more at lower levels than high, and at high levels, most of these abilities tend to get less use.