Is your party doing anything besides going from fight to fight? Is there any exploration or interaction opportunity to use magic creatively? If the campaign is just a series of combat encounters then I would probably want to play another class.
Well, it's HotDQ. Without too many spoilers, we did the Greenest fights. Then we did rearguard. Then we set up an ambush site at rearguard twice (the second one was a huge fight, we were trying to whittle down the bad guys by having them come to us). Then I had a chance to cast Suggestion on a captured foe, but the party was split on which of two plans to use, so I ended up with the idea to go to Berdusk to sell stuff and buy supplies. We did that, but did little roleplaying in Berdusk because we were on a mission to save an NPC, so we were rushing. There were some PC rangers from Berdusk that we met up with, but they were good guys, so no casting spells on them. And then we infiltrated with disguise (where I did get to cast Disguise Self, but only on myself) a dungeon of bad guys where we didn't fight right away, but we eventually did a divide and conquer strategy (the DM did that to us too btw). We now just finished that, went back to Greenest, and are moving on.
I really think that if a Wizard does not take Sleep in 5E, it's a long hard slog.