*Spoiler*
AFAIR there is a statue in the Keeper compound that carries like a 250g tiara (where loot in general is very meager in value)

An interesting one indeed. I believe this is by far the author's best mission.

The loot objective is indeed somewhat high (2800 out of 3300, so 83%?), but not downright unfair. Have you swept the lower levels?

Well if weed is your 1st association ;-o I always interpreted it as just smoking to kill time (cool enough as is). Mechanists are there apparently on notice to collect bodies for their certain project...etc.

The plot (or a system of fleetingly connecting sections of different plots in a day in the life of the City that Garrett is fleetingly visiting) makes perfect sense. Read the readables/hear the conversations/observe the details. Do not bother connecting everything to the basegame timeline or making a sacred cow of it. Thief at its core is best as dark fantasy which many authors nowadays trying to be faithful chroniclers of a non-existent world instead of creating their own enrichments of it (...

Ok now all the other classic (ie pre-ca. early 2k10s) FMs :-) My tentative suggestions: Rocksbourg series, L'Arséne+Emilie Victor series, Calendra series, and as special bonuses Ruins of Originia, Dark Messiah, Dancing with the Dead & more...

Only the last stretch of the approach is linear, the vast majority of it isn't.

This mission may be a guilty pleasure of mine but I respectfully disagree. The level itself is actually pretty complex and I discovered that it's best (and probably meant to be given Garrett's situation and the slightly soured relationship with his principal) played entirely "revenge style", ie using the means you get that are actually very accurately dosed to be just enough (on Expert) to dispose of ALL enemies in the level in any ways imaginable in the Original Ghosting ((C) Civvie) style ...

BTW if you're into the burrick/horn trope try a nice FM that (partly) explores it - Forgotten Tomb.

If one would be really nitpicky it's not entirely undead (souls are a different matter altogether) so you may "do want you're blackjack because those burricks won't boink themselves"

?? Guys it's definitely a some version of TFix thing, I still have TDP to this day as my main installation and I only additionally install what is absolutely necessary to make it work (and play FMs) on a "modern" system, ie afaik TFix.

Rose Garden is not necessarily a good culprit here, I would say it's just as tightly packed as it gets for the amount of gameplay on offer. The coup is that it FEELS that way (ie big) at first by design choices. But yes, the prime notorious examples for unnecessarily big just for the sake of it are many and numerous. Looking at you, Feast of Pilgrims.