Good point, there would still be limits like obtaining spell components and learning the rituals (from someone conveniently out of town for the duration of the crisis), but I also keep forgetting that clerics get more than seven spell levels in later editions. You could have left out or limited the really game-breaking ones, but we see 2e-7th level cleric Resurrection (Withers), a group version of Succor (Return to Camp) and Wind Walk in the game. In 2e, Bards and Sorcerers are using wizard/arcane spells, while Druids, Rangers, Paladins and Warlocks/Shamans use (mostly) clerical spells. Bards tend to have a longer learning curve than "proper" wizards, and I guess 2e-sorcerers are a different animal, as they technically work mostly like wizards, except that they're not using spellbooks and sometimes dangerously improvise things to unexpected consequences. They'd still have to spend time to learn the rituals.
As a necromancer, a nice lab with a smattering of bones, pickled tentacles, brains in a jar and a bunch of quest items spread untidily on the table were a must. At the Dockland Camp this may have escalated a bit, but it was a funny mini-game!
That said, there's also the whole thing in the lore about how the characters have been "Deleveled" by the tadpole.
Maybe it's like just doing a number of levels as a "True Soul [class]", like in 3e, while losing access to your original class(es) and levels. It depends on your head canon, I guess. Sava was a lab potato occasionally venturing into the wild to keep her operation going, so starting as level 1 made sense, with practical experience turning theoretical knowledge into skill, but we know that Gale, probably Wyll and likely Shadowheart, Lae'zel and Karlach, must have previously held a (much) higher level to explain their backstories.
Withers doesn't strike me as the sort who's really big into the whole "Manual labour" aspect of camp maintenance...
This reminds me of a player completely misunderstanding the "shady mystic on the edge of town"-NPC who was helping the player's slouch solve a case of missing squatters in a Shadowrun game as part of his own fight against dark forces. Maybe because he was new to Shadowrun or RPGs in general, the player didn't pick up on any of the horror elements surrounding the NPC or his hut in the woods and thought he'd found some sort of deputy/assistant. "...and make 50 copies of these posters, will ya? See you tonight!" (door slams shut, car starts with tires screeching)
