Having done a quick check on Goodreads, I see that I read 'The Last King of Osten Ard' in May 2017, designed to be a warm up to a return to the world of Osten Ard, and to get us all in the mood for another trilogy along Dragonbone Chair lines.
Well, after a meandering and very long read, I have recently finished 'The Witchwood Crown'. And how was it? Well, I'm not really sure. I think I am pretty out of practice at the whole epic fantasy fiction genre. Certainly it was long, and there was a very large cast of characters to get to grips with. For fairly large chunks of the book, not a whole lot happened - people trudged about, talked to each other, had the occasional skirmish, and so on. I suspect that the same may well have been true for the Dragonbone Chair as well - I think that Simon may well have been stuck in a forest for a few hundred pages towards the beginning. I have no intention of re-reading it right now to check. It's been about 25 years since I read it, and I have plenty of unread books on the shelves right now.
However, Tad Williams does draw you in, I do enjoy his writing style, and if I remember anything from his first Osten Ard trilogy, I seem to recall that he lays a pretty solid foundation, and things start to warm up nicely as the tale unfolds. I suppose as the ultimate seal of approval, I've bought book 2 (Empire of Grass), and I understand that he's busy writing book 3 (The Navigator's Children).