I had no problem at all with the cartoonish blood. For those reasons you mentioned is why it's incorporated. There is soooooo much blood, they need to lessen the shock of gore. It was done successfully in 300 and Sin City to great visual effect.
I'm surprised you didn't mention anything about the dialog. The speech pattern. I was hesitant going in hearing these strange sentences spouted out. But it did not take long at all to get used to it. (I never did get use to all the cursing in Deadwood though).
Whitfield was a perfect Spartacus. All the characters are unique and add so many dimensions to the story telling. It's a fine line of drama and soap opera.