I have a lot of long Hubs and Google loves them. (I have one which is over 10,000 words.) If you are writing content which is valuable for users, don't pay any attention to the length.
As for Hub Scores, people have always complained about them and Paul Edmondson admitted today on the forum that they don't take into consideration traffic or income when calculating Hub Scores. To give you an example, I have a Hub which has had more than 188,000 views in the past year. It has a Hub score of 73. I have another Hub which has had 178,000 views in the past ten months and it has a Hub Score of 69.
Bottom line: Just try to please Google, make some money and forget about the rest of it.