Please do point them out! I'm glad to learn from the better players here; as I mentioned earlier, I really think my success with this build has been more due to Codex being really good than to particular skill with it on my part.
For the Schadenfreude thing, I realized my mistake as soon as it happened. Around the same time, I make two other silly mistakes. First, I forget I have Soul Orb, and spend a ton of time awkwardly playing around the Mana Burners with Entanglement when it's completely unnecessary to do so. Second, because I'm trying to fight several Entanglement targets simultaneously, I end up popping Getanderfix's burn stack, letting them spawn plants. So because of those, I got a bit frustrated, got a bit sloppy... and that's where the Schadenfreude mistake came in. I saw no damage taken on the predictor and went "Oh, it's not hurting me, so this won't waste my Schadenfreude" -- but of course, it was hurting me, Essence Transit was just masking the damage. So, yeah, even at the time I could see I was throwing pretty majorly in that section.
I'm so used to Sorcerers of Mystera going Gnome that I just sort of defaulted to that, since normally they have plenty of max mana anyhow and they're saving a bunch of glyph conversions for the end for Refreshment. But in Naga City, you're forced to convert most of the glyphs before going to the arena, and you're right, between the 13 Mana potions and 2 Schadenfreude potions and 3 walks back to the arena between waves and 5 natural level-ups and 3 Amulets of Yendor, you get so much free mana restores that there's no possible way Elf's max mana is worth less than Gnome's extra potions. You're absolutely right, Elf should work way better.
In fact, I gave it a shot and Elf Sorcerer did, in fact, work amazingly well:
https://www.youtube.com/watch?v=iusRyL2_bQkThe big mistake I remember from this run was using my Schadenfreudes while I had a fully-charged Crystal Ball that I'd completely forgotten about. I think it otherwise went very smoothly. Once again I'm doing the MA-EM-MA-EM pattern, which I know seems goofy but feels like it works super well here.