I guess I am in a minority judging from the other reviews, but I think this episode is just awful. Where to begin? Well, let's see - the character relationships are convoluted and hard to follow, and the characters themselves are generally unsympathetic and in some cases ridiculous. The murders don't make a whole lot of sense - the logic and motivations behind them are weak IMO, and I have a hard time buying that the murderer would actually go through with them. And the comic book festival (with attendees, including "fanboy" Winter, running around in silly costumes) and the competition over the inconsequential sheriff post both just make the whole mess seem juvenile.
The story hinges on the deaths - one in the recent past, one in the present - of two characters, one of whom we see only once very briefly in a flashback and the other of whom we never see at all. We learn so little about either of them that we have no investment in what led to their fates, and thus the motives for the subsequent murders fall completely flat. And as another reviewer pointed out, there is a glaring plot hole: Why wasn't any headway made by the police in solving Lord Argo's murder and the attack on Francesca at the time they happened? And, why does Barnaby act as if he's learning of that case for the first time? - he would have already been in Causton by then. Apparently not much thought was given to the continuity aspect here.
A sorry piece of writing this one is. The actors do the best they can, but to no avail. "Drawing Dead" is one of the most boring Midsomer outings I've seen - watching it I found myself barely able to stay awake, let alone muster up any interest in what was going on. Grade: F.