The SLA's for necromancy and evocation just aren't as useful as the enchantment, or even illusion ones, either.
Hypno SLA is nice, but Hold Person is awesome. It's a fairly short cooldown and only costs 6 SP, and it makes the mob helpless, taking more damage from melee attacks by my party. I found it indispensable from the time I got it until I TR'd. Resistible Dance is highly underrated, as unlike Hold Person, this works on all enemy types (except those immune to enchantment, of course, like scorpions). I also found it worked more often on high will-save mobs like casters and clerics than Hold Person and isn't affected by FoM. I would charge into the fray, toss down a web SLA, then proceed to dance and hold every mob in sight, then launch an AoE or make sure my party is hasted and raged.
It's also about party dynamics and difficulty. On EE, enchantment SLA's (and enchantment in general) are better than FoD and wail, in my opinion, due to their low cost and ability to make enemies vulnerable to dps classes. Using 50+ SP on a failed FoD is a let down, where 3-6 SP isn't a big waste if it fails.
So, I can CC an entire group of enemies with a few low SP enchantment SLA's, or I can use wail and Fod, and use 8-10x more SP in a fight and hope I don't fail my DC's. It's a matter of flavor. Both work exceptionally well, but I think this current obsession with necromancy is boorish and so 1980's.