I knew the conversation would go this way from the first couple of posts, so I've only skim-read most of it, and this may have already been said:
Yes, reduce damage from summons, but also
increase experience gained from support spells.
This way, more conjurers will grind with a support setup, meaning there's more teamwork in the wz, the conjurers that grad have a better idea of how to support, and the game would generally be more fun, since when they step out into the warzone, they'll have some idea of what they're doing and increase how long fights last, because players on both sides would be well supported.
Conjurers, being the main support class, should not be insanely hard to grind, but summons can give them too great an advantage.
Also, @ warjus in general - for crying out loud, DI your zarks