Don't you organize your spell by level on your character sheet? Also, maybe there is too many spells in this game and too many spell slots per class.
They're game designers, they should DESIGN their game instead of being all wishy washy and just basically dumping all the work on hapless DMs. Can a Rogue hide during combat or not? It's a simple Y/N question, and the answer impact the perceived strength of the class and the ease of the use of Sneak Attack. What is the INTENTION here? It SHOULD be answered by the DESIGNERS and then if the DM wants to disregard it? It's their prerogative to weaken or buff a class.
Like, to me, Sneak Attack should be occurring EVERY turn, because it's how the Rogue keeps up with the others damage wise, and it pushes the Rogue to act, well, like a rogue. Why else would it proc if you're just attacking a dude next to your allies? Advantage itself can be harder but you don't need it for Sneak Attack. Some DMs seem to think it should be difficult to get Sneak Attack and that it is a 'bonus' the Rogue gets instead of a baseline level of damage (probably thinking of the 2e thieves too much). Knowing which one was the expectation of the designer would be very useful.
A bit off topic but: It really annoys, and baffles, me that, somehow, transparent game design is seen as a BAD thing?! Augh. DM-ing is a form of game designing, SHARE your damn design notes with the DMs, WOTC, they're your fellow designers! And DMs should really stop being so obsessed with their own immersion, you're already BEHIND the curtain directing the play: stop complaining that you can see the stage hands!