To me also it's actually a 7.5-7.75/not a straight 8 due to the slightly repetitive level design/assets/secrets approach and no surprises/unique situations of any kind but still a clear step forward (not least in overall conciseness) from Into the Dark Forest Rem. where some parts of the map were just entirely redundant run-throughs (and there's again no shortcut of any kind to get back to the start once all is done but this time it's at least less gross given the slightly more manageable mis...
Kept Away From View: just follow the courier, erm rogue, erm keeper* (*according to campaign authors).
The transformation in the library could have had some real impacts in the campaign, as it is it feels ultimately very self-contained (and references to something that plays far after the originals should have been kept to a minimum) - that and the weirdly mechanical feeling about the sanctum's layout and (far too regular) geometry, as if made first using an automated tool and the rooms ...
There's not just a sword (blade) with holy weapon and other interesting properties you can get easily in this (2nd) mission but also and notably a very complicated, cool & awesome scripted procedure (with an equally cool guide) to get an even more potent AoE (mostly) one-shot weapon against the undead (with limited charges so to be used wisely), one of the ingredients for which also functions as a "sort of" funny lesser weapon, in addition to several holy water potions, one of which again in...
It's a shame you haven't played Calendra's Legacy first. That's the Source.
In addition to the above recommendations, also interesting puzzle missions (or at least partly including puzzles): King Abedzen's Tomb; Secrets of the Old City; In These Enlightened Times
I see you already played the likes of Beneath the Sands/Whispers in the Desert, Temple of the Tides, Forgotten Tomb and so on
Also one big environment puzzle of a classic mission of an entirely different kind: Thief: Brainchild