I also didn't like The Path of Daggers the first time I read it, but for several reasons.
The first one is the one you mentioned; I was very disappointed that character did not appear in the book.
Second, the first time I read the WoT series was in 1998-1999 and at that point tPoD was the most recent of the books to be released. For that one to be the last book I would have to read gave me, well, not much to look forward to. On my several re-reads of the series since, I have come to enjoy it a lot more, but at the time I found it pretty dull.
Third, and this is connected to the last reason, this book is pretty anti-climactic. While a lot of stuff does happen at the end, it's not really suspenseful. Of course, when you have Winter's Heart sitting there just waiting for you when you're done, that's not really a problem. When you have to wait a year and a half...uggh.
Last, this book might be the most confusing of all of them (maybe CoT could rival it). I got really bogged down by the political maneuverings and the vast amount of main and important characters' storylines. Additionally, when you compare this book's timeline to A Crown of Swords, it seems like it's taking forever for things to happen (aCoS takes place over a week, tPoD takes over a month). When you consider that much of that time is spent travelling (and I'm not talking about the One Power kind), or sitting around talking about going somewhere.... Granted, this book does a lot to set up for the conclusion of the story, but during the first read, it's a bit rough. My wife just finished this book a couple of weeks ago during her first read of WoT and she also found that one the most difficult to enjoy and comprehend. I guess it's like vegetables - not that great the first time, but you later come to appreciate their value.