Your player is... well, let's just say he isn't reading the spells carefully, or the relevant rules.The title describes a conversation I recently had with a player. He likes to build characters of all types - not necessarily a min/maxer, but tries to embrace what a class is good at it. He could not come up with a fun build for a rogue. Almost everything a rogue does - the wizard does better. Knock, Invisibility, and other spells are effectively better than the rogue's skills.
Knock in 5E is virtually useless. It makes a noise that alerts everyone within 300 feet! You might as well just hand a sledgehammer to the party fighter and save your spell slot. I don't think I have ever once seen this spell used or even prepared.
Invisibility is useful, but it does not excuse you from having to make Dexterity (Stealth) checks--it just gives you the opportunity to do so without needing cover. If you blow the roll, you will be detected regardless. As a result, invisibility is most effective when used as a buff for the stealthiest PC. The invisible wizard and the visible rogue are decent infiltrators, but an invisible rogue is vastly superior to either.
Um... no. Rogues can do far more than scout. They are highly mobile combatants that can deal a lot of single-target damage, and their opportunity attacks are devastating. Expertise and extra skills allow them to be exceptional party faces, second only to bards.To make matters worse, the thing the rogue does semi-decently is to move ahead of the party and scout the situation.