I can say magic missile is not at all a must because I've not used it once on my sorc.
In any case, I don't think the aim of DnD is to have all spells be equally useful.
If you think fights don't last long enough for you to be able to get value out of defensive or buff spells, I have to imagine you're not playing on tactician. Because fights can definitely take a long time and often do. A twinned haste in one of these long, hard fights. I've also found sanctuary to be very clutch when someone is on the verge of the death. And then while I don't cast bless there is a ring that gives bless when you heal someone, which is nice when paired with AoE/multitarget heals.
After act 1 I wasn't even able to play on balanced lol. Well I could have maybe, but then the reloading would have become so tedious it would ruin the experience for me. Balanced felt like tactician, and the high difficulty actually shortened the fights, as I was downed before I had much chance to fight back. Didn't know my sorcerer could cast twinned haste lol, I could have used that I guess
