I'm sceptical but also optimistic (same with LOTR, though I think it's going to be hard to avoid comparisons to Jackson's trilogy, which was a masterpiece)
I think a lot of GoT's failings can be attributed to David Benioff and D. B. Weiss, as they rushed through the ending as they wanted to go off and do their other projects, turning down time, episode and money extensions from HBO
They're not involved in this new series, and also (as mentioned above) all the info is already in a book - it's not like GoT where they had to wing the last couple of seasons
Also HBO (and the new showrunners) will be VERY aware of the public opinion of the ending of GoT and won't want a repeat of that
Also also I've just seen that Ramin Djawadi is doing the music, which is great because the scores in GoT were incredible
I'll have to give Fire & Blood a read, I think I've got it somewhere but never got round to reading it because it's a physical book and I'm a kindle kinda guy these days