Despite what you may read elsewhere, BFTA is not a total disaster. Yes, it has very poor character development, yes it is riddled with tired stereotypes and cliches, yes its poorly edited, yes its not a patch on the first four books (I liked Fulgrim, worth the entrance fee for the opera scene alone).
The final quarter of the book shows great pacing, however, and is genuinely exciting as it races towards the sadly obvious conclusion. Good writing in this genre, I think, is measured by 'movie moments' - scenes and set pieces where you can visualise the action in your head as it would appear on the big screen, with a worthy director and unlimited budget. Mhotep's struggle with his demonic adversary is one such moment, as is Cestus' journey through psyk-induced hell, Brynngar squaring up to Balenos (sp) for the second time...its just a shame that you dont care about these characters in nearly the same way you cared about Loken, et all.
This series has really lost its way, and I do not think that this is the fault of the writers. GW, in true GW style, obviously sold a shed load of books to start with and realising they had a genuine cash-cow on their hands seem to be hell-bent on making the series last as long as possible, to make as much money as possible, and are probably putting pressure on its authors to churn out books as quickly as possible to keep the momentum going. I think BFTA is a good example of this - Ben Counter is not a bad writer, as he showed admirably with Galaxy in Flames, but this feels horribly rushed. In addition, as with the awful Descent of Angels, BFTA is very much a 'filler', that really does nothing to move the story on. There needs to be a strategic rethink on the whole series, as if things continue as they are, by the time the end of the saga is reached, there will be no-one around to care.