It's been a while since I read them, but I don't agree with that assessment. I, Claudius is dense and often exciting but it can sometimes feel like a long list of things that happened. Claudius the God is paced a lot more slowly (often too slowly) but it allots it subjects more room to breathe. It works more as a character study. The ending represents a satisfying and genuinely affecting conclusion to Claudius's own character arc.

I would say that my biggest problem with both books is that our understanding of Roman history and how and why it was written has evolved a lot since the thirties, and it really shows, particularly with the characterisations of women like Livia and Messalina. I can't attribute that to Graves, though.

Now, if you see what a truly tedious Robert Graves novel looks like, read Count Belisarius...