So let me get this straight, rather than a quirky, self-referential riff on / tribute to Internet communities, which is admittedly a weird concept but I hope you'll find to be executed with a pretty thorough internal consistency and logic, you'd rather we'd made another bland military near-future shooter or even just tried to stick to the Deus Ex universe, doubtlessly brutalizing it as only the worst fan fic is capable of?
It's hard to explain why TNM works, but I can give it a shot - bearing in mind that I'm the lead designer, so I'm not exactly unbiased. I know your legendary elitism around here, which is fine by me, but bear with me.
We've worked on it for 7 years because it took us 2-3 years to learn how to mod in the first place - we estimate that pretty much nothing of what was done in the first 2 years is still featured in the game, everything has been redone. That constant iteration over such a long period has allowed us to develop the setting and the story quite organically instead of sitting down at the beginning of the project and figuring everything out, which would doubtlessly have made it easier to develop, but a lot less fun for everyone involved.
That also means we've had plenty of time to get people other than ourselves to look at it, and though the final plot isn't entirely free of holes and weaknesses, I think it actually holds up pretty well and has some decent punch where it counts.
The greatest problem in describing TNM is the humour. Most of the humour in the game comes from the strangeness of the setting rather than the actual plot. The plot is weird because of the setting, but replace the faux-internet factions with real-world conspiracy groups and it would probably transfer pretty decently into Deus Ex's near-future-real-world, uh... world. What "jokes" we do have in the mod generally aren't punchline-based but carried by humourous phrasings or intelligent quips - I like to say I prefer humour based on intelligent people being intelligent rather than stupid people being stupid. In general though, TNM is not a comedy game, it attempts to find a balance between being serious enough to immerse you and not taking itself too seriously. I'm definitely not the right person to judge whether we've succeeded on that count, though, so I'll happily leave that up to you once you've played it
Finally, I would like to admit that I am certainly not Lawrence Kasdan, but of the ~195,000 words of dialogue in The Nameless Mod, about half of it was written in the first 2 years of development, and all of that has since been rewritten - the script has undergone constant changes and ruthless editing, most recently as our (surprisingly good, if I do say so myself) actors have put their own spin on the characters, lending them personality that I didn't always have time to infuse into the writing.
tl;dr: Please give it a chance, our attempts to describe what makes TNM good don't really do the project justice. If you still think it sucks after you've played it, so be it, but in theory at least, this mod should really hit the RPG Codex sweet spot*.
* Well, okay, it has no turn-based combat, but aside from that...