Some suggestion about a few weak spells:
All Summon spells: could use an enchantment line to summon lesser/.../greater monsters (animals for rangers).
Or maybe allow more summoned but different lvl monsters. 1-1 for conjuration focus. Or both.
Lightning spells: no high lvl version. A short time stun effect enchantment would be nice.
Acid spells: attack/dmg/AC/maybe DR debuff with a new enchantment line could make it more usefull.
Horrid Wilting: In BG it was a party friendly spell. In DDO almost every spell is party friendly. The dmg is too low.
Mind fog: As Aesop mentioned before, a refreshing save in the fog
Flame arrow: Converting this to elemetal arrow, and choose from a list (like elemetal resist), plus changing it to a short time buff (like haste).
Tensor's Transformation: Make the stats stackable, and it will be okay, or at least not completly useless.
Grease: Heighten. I want my teammates fall!
Create Undead: Should be free for pale masters. But at least remove the material component.
Slow: Mobs outrun it. Bosses immune (not even a few negative stat on them :/ ). Later against higher lvl mobs Hold spells comes to my mind.
Power word Kill (and the rest): Maximize and Empower should work with it.
Incendiary Cloud: Wall of fire is better for less mana.
Teleport spells: More location please.
Symbols: too long cooldown
False life: why is it capped at lvl10?
Hold Animal: Once in every year when a ranger land a spell on something, the animal get a new will saves every 3 sec? How about no will save at all, but last only 6-12 sec long?
Spike Growth: Not even a zombie will fail a reflex save vs a ranger spell.