I think that Bless should not consume any memory - it's mostly a quest related skill (besides saving the pigs on fire and the historian I found not much use for it, and as soon as things like holy fire become truly interesting, much stronger source skills become available which compete for memory).
Where I strongly disagree is with nerfing Summoning. It's one of the most fun ways to play the way it is now, nerfing it would lead to less viable party compositions.
