Edit: not saying they need more defence, but their offence should be worth the tradeoff.
This. For increased defenses, I might still consider displacement as a nod to its semi-thematic nature, but probably not anything else (bear in mind they may be getting the opportunity to take Venom Immunity, per another recent suggestion thread). That said, what do you all think of the following list?:
Ray of Enfeeblement Blindness/Deafness Hold Person Enervation Fear Cloudkill Feeblemind Circle of Death Eyebite Rebuke Antipathy Horrids PWK
I'm especially curious as to people's thoughts on how it effects incentives to take spell foci, as per Raj's point on PWK above. Usefulness of a given spell is a relevant consideration, but do bear in mind that, with every area, we strive to make more spells useful.
This list is going in as BK spells next update, with help from Jean.