I actually like evocation. Sure, it's a hammer school, but sometimes you meet nails.
1st - Magic Missile. Sometimes your only option at helping an encounter is doing reliable, even if lowish damage. Once you're done buffing, or are reluctant to waste higher level spells, this is a nice thing to have. On par with a Reserve feat, and obtainable via the Gloves of the Starry Sky.
2nd - Frost Breath. Reflex Save or Dazed. What other school has a Reflex save or die?
3rd - Sonorous Hum (lets you cast other spells while concentrating, unlike the skill trick, and doesn't cost you a Swift Action every round), Ray of the Python (Prevent Full-Attacks, AoOs and reduce speed with NO SAVE for the first round, and a Reflex save later).
5th - Boreal Wind (damage + Battlefield Control), Sending (Tell anyone, anywhere, anything).
6th - Chain Lightning (20d6 damage at a 6th level slot is CHEAP), Contingency (This one doesn't cost XP nor gold to use, and can be replicated by an 8th level spell that might not work, depending on your DM)
7th - Stored Lightning Bolt (2d6/CL, no Save, and with an added area damage? Sure), Radiant Assault (15d6 AoE, Will Half, Daze if they fail for 1d6 rounds), Forcecage (!), Grasping Hand/Ice Claw (GRAPPLE GOOD!)
Those are just off the top of my head. There are worthy spells in this school. True, unless you're a blaster, many aren't as useful, but being able to do something to the person you'd just used Battlefield Control and Debuffs on is generally useful. And I don't know about you, but an AC of 40/50 on CR 12 NPC is not uncommon for me, so Summons just won't cut it.
I'd generally get rid of Enchantment first, Necromancy 2nd, and if going Focused Specialist, Evoker 3rd. And then, only because you have so few non-in-school slots free, and those tend to go to the school you didn't specialize in of Tran/Conj.