I can totally empathize with the author. A couple games that I've had this experience were (and need to go way back):
1) Ultima VIII - As someone that started playing Ultima III on a C64 and played both the Worlds of spin offs, I was super excited for this game. I ahd a subscription to some game magazine that had almost monthly updates on the progress of it. I would come home from school, go straight to the mail and if my new mag was there, read every word about it. Then I got it. And it just didn't grab my attention. I was annoyed. It didn't feel like Ultima. I sadly put it away and lost my self in Civ II for a time.
2) Ultima IX - After the disappointment of U8, I eager anticipated U9, especially after reading articles about how they had 'tried something different' with U8, it hadn't worked, and they'd learned from that. I got my first look in the extras part of the Ultima Collection, which had a demo of U9. I wasn't 100% sold on the 3D aspect, but in Lord British I trusted! Once I finally got it to run on my PC (which was a chore in itself), I never got more than an hour or two into it before losing interest. I think it missed me for three reasons: 1) I didn't like the 3D aspect, even if it was beautiful. 2) I prefer party based adventures and 3) again, it didn't feel like Ultima. This really soured me on 3D rpgs. It wasn't until playing U5:Lazarus a year ago that I got into the 3D aspect.
The good thing about U9 was that I picked up a copy of Baldur's Gate to tide me over until U9 was released. I'd never played a forgotten realms game before and wasn't sure if I'd like. Now I'm obsessed!
3) Icewind Dale II - I was disappointed with IWD: Heart of Winter, like everyone else, but satisfied with the Trials of the Lure Master free download. However, IWD was just great. After completing BG2 and seeing that IWD2 was coming out, I was stoked. Again, downloaded the movie demos, read the developer journals, etc.
As it was obvious that 3D isometric games were quickly becoming extinct (and I was still anti-full 3D), I was happy to have at least one more installment. Two things killed it for me though. The first was simply I didn't care for the 3rd Edition rules. I think they fixed a lot of the problems with 3.5, but it just seemed TOO flexible. I could have dealt with that though, but 2) I got lost in the story. After a few hours, other than knowing from the journal that I need to go to some specific place, I had no clue what the story was about. Couldn't even really recall the intro or anything. The story makes it for me, so this was a killer.
4) Neverwinter Nights: I followed this one on BlackIsle's website from the beginning. I had high hopes given BI's reputation. Then suddenly, it was gone from their site due to some contract issues. Regardless, I was willing to give 3D another shot, and the idea of a game that was designed to allow you to make your own campaigns REALLY excited me.
If I had the time time play online with groups, I may well have liked this game, however trying to play the OC killed it for me. I HATED the henchman concept, still didn't care for the 3rd edition rules, and the OC story was awful. When I gave up, there still weren't many user modules out there, and since I cared so little for the game, the idea of making my own fell off as well.
I probably should give it another shot, but I've moved on.
5) ToEE - One last chance for 3D isometric! Played it for about 2 hours. Hated the full turn based combat (even if it is more 'authentic') and didn't like the mapping.
Right now, I'm having trouble getting motivated to play MotB. I really liked NWN2 OC, but the last chapter my enjoyment fell off. as such, even though I KNOW I should start up MotB, every time I think about it, I do something else!