I don't have issues with any of the spells... I only have issues with my players and their decisions on which spells they choose to take.
Is Fireball "overpowered" compared to other 3rd level spells? Yeah, maybe, but that doesn't bother me. What bothers me though is the player who says they want to play a Necromancer in theming and background... and yet throws nothing but Fireballs during combat because it's the "best" 3rd level spell. To me, if you want to play a necromancer, play a necromancer! I will be helping you out to be the most interesting and best necromancer ever! But I won't if you just default toa metagame idea of "I want to make sure we win at all the combats!" more than playing a thematically consistent character. That's the easiest way for me to just shrug my shoulders and lose interest in your character's progression through the campaign. I'm fine with you playing your character that way and won't stop you... I just won't be all that enthused about trying to spotlight your PC at various points in the story because there's nothing to hold onto.
I think there is a very specific issue with the necromancer wizard just not being a very good/flavorful "necromancer."
I am starting a campaign now with a player who wants to play a necromancer character, and looking at the options, the Undead patron warlock, the College of Spirits bard, the Shadow sorcerer, and, in a weird way, the Circle of Spores druid all do a better job at "feeling" like a necromancer than the necromancer wizard does.