Well bear in mind, the damage from the Death bless is AN, and they get 2 attacks. So while beating on particularly tough thugs, even hits that don't do damage otherwise will still do magic damage, and therefor cause afflictions.
I'm not sure if it's fair to say that the mid level evocations are only useful for straight kills. It's quite common that Falling Fires or Fire Cloud can be used to soften an army (not fully intentionally, just the mages spamming them loosely around, as any kills reduce the efficiency of casting again in the same spot), so that when the lines clash, no one is likely to survive the first hit they take. However with the Afflictions, you get Cripples and Limps which will break their formations and pin troops inside the Fire Clouds, and many of the other afflictions reduce attack or defense capacity, thereby increasing the efficiency of your infantry once the lines do meet.
And then you have single target spells like Combustion and Incinerate that have 100 Precision, so if you are coming up against sacred giants, or top end summons, you can really be sure to weaken them as you get your first licks in.
Now, really, it all comes down to how you want to play, and what you want to push. Also, what you expect to face in the game. Obviously if you fear starting next to a rusher, a Death bless is going to be a valuable deterrent, as their key units are nowhere near as replaceable as they would be in the late game. As the game progresses, it becomes a matter of what you really want to stress in the game. And then also I guess what it really comes down to overall is whether you want your pretender to be awake or not. With an awake SC you of course will want to min/max as much as possible, especially in terms of what you can accomplish in the early game. Like I said, my philosophy with Abysia is that their troops are solid and dependable, so you don't -need- an awake SC, so personally I would prefer to have him Dormant, and roll those extra points into perhaps D9 or E9, because I would feel that the direct boost to the pretender's abilities are the final key to it being "cost effective".
And yeah Dirty, I've played around with a Fountain of Blood with Abysia, I like the dousing bonus, and a few extra strength is nice.
With a Dormant VQ you can get 6D/6B with decent scales, but with a Dormant Fountain of Blood you can do 6D/6B with Dom7 O3/P2/H3/G1/L1/M1 which I don't know, looks really solid to me. Gets you +200% Affliction rate, so 3x as many isn't too bad, and 3 Str. And 6 in both leaves you in a good spot for most spells, as well as giving you basically full access to all Blood summons AND Death summons..... not sure if that's just too much to worry about, but with the research bonus, why not, eh?
I'm curious though Moderation, what sort of pretender would you actually lean towards?