I've been doing a sort of re-read lately myself, mostly opening one of the books and rereading certain scenes I like. And not doing it any coherent order either.

Two reasons they go along with it. They dont say screw prophecy because they're afraid it would make a third possibility appear, and that would mess things up more. Second, at one point Belgarath comes right out and states he tried it before and it did no good because the two Destinies are actively manipulating everything no matter what he does, and it actually put him further behind.

Yeah, Ce'Nedra is probably the most useless character in the series. Possibly she's there as a token female character, but she's incapable of doing anything useful. Polgara's a sorceress, and in the Mallorean we get Velvet who's at least a spy, but Ce'Nedra's just a spoiled brat. She's not too bad in the Belgariad where she's playing the spoiled princess archtype to the hilt, but she ges her maximum uselessness in the Mallorean where her purpose is apparently to be possessed by Zandramas whenever the plot requires it.

This is my take on the whole saga:

The Belgariad is a pretty good coming of age story. Nothing's all that spectacular about it and you can see the plot "twists" coming from a mile away, but it's still a light, entertaining read. There's a few uneven parts here and there though.

The Mallorean is the weakest part of the whole saga. There's a lot of rehashing going on and even the in-story justification about things repeating is weak. Some parts are good, Guardians of the West starts things off on a high note in particular, and it's probalby the best overall book. But the series feels likes it's padded out in some places, particulaly in the weakest volume, Sorceress of Darshiva.

Belgarath the Sorcerer is probably the best book in the entire saga. Eddings' writing shows a good deal of improvement after going through the Elenium and Tamuli. This book does retcon the earlier books, but it's not a bad retcon in particular, the retcons I think help to tighten up the narrative and make it more coherent.

Polgara the Sorceress is a serviceable ending to the overall saga. It's a step down from BtS; some parts are a bit too silly even by Eddings' standards, and the parts the rehash the evens from BtS are actually kind of dull. OTOH, the unique elements, particularly the parts that describe her centuries in Arendia and her protecting the line of Riva are the best parts of the book. I'll admit right off I always hated Polgara until this book actually fleshed her out a bit.

Biggest problems overall with the books are these:

1: Everyone from a certain kindgom is the same. So all Drasnians are sneaky and devious, all Tolnedrans are greedy poliical backstabbers, all Murgos are arrogant xenophobes who think they're the pinnacle of humanity, etc. After a while everyone starts to seem the same, there's no real individuality.

2: The sheer amount of medieval stasis. All these kingdoms have existed for something like 5 millenia and haven't really changed much in all that time. And I don't buy the divided univerese keeping everything from progressing argument given in the story. Both Belgarath and Polgara do give us some indication of historical development, but not much. And the one thing tat usually keeps such social stasis goin tends to be magic, which is pretty rare in this world, so just where is all the social and technological development that should be taking place?