Conviction is pretty good. Not sure if it's broken, but it's very nice.
Planar Exchange is kind of wierd. Haven't tried using it or seen it used once yet, though, so hard to judge. I do know that in the current game I'm in/running, it's a 34 point buy gestalt, so a quick glance at all the forms makes me think "that thing wouldn't survive too long in one of OUR fights..."
Close Wounds is one of the best spells ever put in a splatbook, I would never dream of banning it. Delay Death is almost silly, but I think you still need the Diehard feat if it's cast on you to make much use of it as your hp goes into the negatives, and IME not a single PC has ever taken that feat.
Sound lance isn't broken, though it is a divine spell, and thus a pretty good spell due to divine casters' lack of powerful evocation magic. They did gain a bunch of blasty spells in SpC, though, so it seems pretty clear to me the deigners intended to expand their arsenal a bit.
I don't think Radiant Assault is too powerful. It's basically Fireball with a level-appropriate dice cap and untyped damage. Direct damage is weak, I think Polar Ray and DB Fireball taught the designers that there needs to be an extra oomph for high level direct damage spells to be worth it, versus empowering/maximizing lower level ones. The 1d6 dazed rounds on a failed save is mostly what makes the spell worth learning. Maybe reduce it to d4 or d3 if you want, but not down to 1. Just my opinion.
There's that spell that removes half the target's hit points, without a save. (I seem to remember there is a save against secondary damage, so Mettle can foil it.) Night's Caress, maybe?
I think you're talking about the Necromancy spells, both are high level. One is Avasculate, the other is Avascular Mass, iirc. Not sure if they're boken or not, but they are very strong, a good reason to not pick Necromancy as a banned school.

And I think the save is against being dazed or stunned for a round.