Correct me if I'm wrong, but doesn't bless also lower food consumption and grant extra luck?

Luck, yes. Food consumption, no (that's a separate benefit of crowning).

It also gives +1 PV. It's a really nice, cheap spell.

Although I don't think it needs anything extra in terms of regular effects, I'd like to see some extra benefits to knowing it, in the form of special-case uses.

For instance, perhaps blessing certain NPCs could produce some sort of effect (there could be a similar functionality added to holy symbols, perhaps, but with harder conditions for generating the blessing effect). I could see, for instance, blessing shopkeepers of the same alignment (I assume they have alignment...) resulting in a slight discount in their shop. I could also see blessing, say, Bart, having the effect of him offering you some item - I could see it being, say, his old shield (a small adamantium shield, perhaps?), or maybe boots of speed.

Alternatively, I could see blessing Bart (after giving him the Gladius) being the first step in obtaining Celestrix (which I'd like to think will become available in 1.2). It would be pretty cool if Celestrix became the point of a trading sequence, especially given that one of its effects is a large boost to charisma. Also note that it would be appropriate if the process to get the Golden Girdle began with giving away the Golden Gladius.

Bless is so cheap that IMHO getting rewards by blessing friendlies would be a very cheap way to extra benefits. But I have added a bit of scaling to the bless effects... only minor but still.