I like other missions of Kung Fu Gecko (Bloodstone prison and Embracing the enemy) that he made after this one, but Library was mixed bag for me since it has hazardous combination of a) quite complicated layout which looks samey and - a bit - uninspired and b) very steep loot objective. Thankfully it was short, but his other missions are much better than this one. Though it is justified for me that it was one of the first exercises in making missions - both for author (it was his debut) and...
This campaign has its ups and downs. I believe Tears of Blood is the shining gem, where despite it's very early FM-era simplicity it shines in almost every other facet. Broadsword of Sheol is another solid mission, a bit overhyped but definitely an atmospheric and engaging mission from start to finish.
Then there are the other missions... Walking the Edge is fine for what it is, but nothing special. It feels a bit underwhelming when compared to its contemporaries released around the same ...
Good mechanists/undead horror mission. Even quite original. For me two biggest issues with this mission were: 1) too obscure and complicated objectives with vault and Amulet (ok, the last one is optional on lower difficulties) and 2) loot objective (loot is too scattered around the level - and it is major flaw of mission).
I doubt there is any cyberpunk-style missions. Only maybe some futuristic FMs like Sliptip's Kill Factory series (especially, Escape From the Planet of the Robots), or Spoonman's TSR-1000. Three Distinct Adventures by Cardia. Also, maybe, GORT's Rebellion of the Builder (hard, as I've heard).
Valky, I don't know much about Deus Ex style exactly (how it could be done in Thief) but colored lighting was implemented in Thief 2 and is in the lots of FMs for T2. Maybe I misunderstood you. As for stylistic similarities - I honestly don't know much. i've said about train mission in T2X and Konrad told you about Patriot (it's a hard campaign as I heard).
And - if you want to experience some stylistic or plot parallels between DX and Thief in Thief fan-missions (though it is really une...
Well we already have a train mission in Zontik's Patriot campaign:
https://www.thiefguild.com/fanmissions/9350/patriot
The train is rather short and it's a cargo train. The mission is quite linear, too. Thus I agree with you that something more sophisticated would certainly be fun. Some time ago, I've seen somebody working on a project like this. I remember screenshots, but I forgot who that was now. Anyway, passenger trains are an excellent place for criminal stories, pickpockets and big...