Everyone else pretty much tackled what I was out to say (and thanks, fellas) about the many changes "in" Land of Promise; they weren't really in LoP at all, I just tried to wrap them all up after the fact (often years after the fact), because prior to this they were all scattered across multiple books (and multiple editions, in fact).
If anything, I think you can get more mileage out of the original Tir Tairngire post-LoP. I tried to take a step back from the "Disney Wonderland," the metaracial harmony, the open borders, etc, etc. At the same time, I was out to strike a balance between the old TT and the newer, more open and available for gameplay, country. It's not my place to straight-up retcon things like the Immortal Elves being ousted, Zincan being High Prince, or the democratic election of Princes to the Council. At best, I could explain all of that, work it in with the Tir as we knew it back in 2nd edition, and just try to make sense of it all. As I told a few of my fellow freelancers when nervously showing them first drafts, I was trying to dial things back, so that the Tir wasn't (a) an unplayable "elves are better than you" zone with unbeatable security and Initiates behind every blade of grass, but also (b) unrecognizable from the classic Tir, because Nigel's seminal book is one of my favorites and I didn't want to wipe it away completely.
So I was basically out to wrap up the ongoing "coup" stuff (it had never really been detailed, the new Council hadn't even been introduced, since it happened almost ten years ago), stabilize the Tir into a recognizable (but playable) form, and...here's the tricky bit...do all of it inside my word count. As it was, I was already way over (that entire intro fic, for instance, and all the NPCs in the back, were stuff I basically didn't get paid for, because I used up MORE than my initial word count on the rest of it, anyways).
I did what I could in the space I had, trying to tie up some things, re-reveal others, and introduce a new batch of Tir Princes. I'm sorry if folks aren't happy with the eventual outcome. I want people to like the stuff I write, but especially when it's something like LoP -- which was "my" baby in that I made the pitch to write it because I thought it needed to be written, just to try and make sense of that particular corner of the setting after it was whip-sawed around all these years.