So, the great unclean has every characteristic bar infamy as a multiple of 7, Nurgle's sacred number (except for one which is 43 and 4+3=7). The digits of its wounds score add up to 7. It has an effective psy rating of 7 when it uses its powers.
Ditto for the Lord of Change and the number 9.
I see no such love put into the statblock of the Bloodthirster. For shame, FFG. I hope the updated stats for the Keeper of Secrets do justice.