Good lord, this option is nuts for people with the feats to spare. Take a look at their powers:
Encounter
[spoiler]
Horrific Maw Bite: Meh. You can do better than this, but the damage is at least decent. It cancels out Power Attack or Spellscarred penalties at the low levels, and overrides them at the mid levels (not worth it at Epic).
Plague Lash: Warlocks like it, and you can boost the damage thanks to the Adventurer's Vault. It's meh, but still decent for a 1st level Encounter power.
Spelleater: Githzerai and Wizards love this idea, while Paladins can make use of it.
Plague of Rooted Majesty: Situationally useful, may see play against Solos more than anything else.
Scar-carving Blade: Not too shabby.
Call of the Plague: Ouch! Pallys want this badly.
Plaguefire Body: The new IHS.
Reach of the Doomed: Reach 3. WTF?! 2[W]+2d10 poison damage if both hit, and the target is dazed if the second attack connects. Costs a Healing Surge, which Pallys and Fighters can afford with ease.
Cursed Grasping Air: Ok, this is great for Controller builds. Wall of fire between two enemies, they move apart, and you put them right back to the wall.
Venomous Bloodfang: It isn't bad, but Reach of the Doomed is better for melee builds.
Scar of Blue Wings: Flying is nice.
Tears of Fire and Blood: It helps if you use this with a daily ability.
Lines in Burning Sand: Wizards want now!
Spellmother's Embrace: Meh.
Body, No Body: Insubstantial is nuts.
Healing Flesh of the Infected: Not worth it. Clerics and Pallys have better tricks.
Iron Tooth of Bloodlust: Meh.
Mask of Midnight: Blinding every creature in a Blast 4 is sick. Pallys want.
Hideous Tether: A Pinning weapon means you can effectively immobilize two people. Maybe more, depending on the build.
Tongues of the Earth: Note that the second d10 and the Int/Wis/Cha damage is acid, not just the score's damage. Pallys like being able to shut down mobility.
Shifting Wave: Swordmage! Pally!
Impossible Flurry: Low damage, but nice size.[/spoiler]
Daily
[spoiler]Burning Focus: Neat trick. Decent if you can afford it, but not worth the multiclassing feat alone.
Spellmirror: Take a look at how many creatures have secondary effects on their own abilities. Only a handful of them (dragons namely) are resistant to their own damage types, but none of them are immune to the secondary effects, which makes this ability good.
Blurring Blade: Even if they save, they are still taking the damage if they are adjacent to you while you are in this stance.
Terrible Imposition: Let me get something straight: You are untargetable, but you can still fuck them up? And you have a nice range on the ability? Pallys want, now!
Haunting Reception: Rogues love this idea.
Burning the Plagued Bellows: Anyone who uses a reach weapon can use this to great effect. I don't see Fighters doing much with their Minor actions anyway...
Submission of the Earth: Assrape them, and deal damage!
Infliction of the Flamemist: Swordmages can all ready give someone Vulnerable Fire 5 or 10, so if it stacks this attack is great for them. Controllers also have options with this.
Rabid Chain of Steel: Great against minions, not against Solos.
Spellcurse: More love for Striker builds, and anyone with a reach weapon!
Gravity of Moment: Can we call this broken? Wall fo Fire is so stupid.
Donning the Mudflesh: Controllers like it, Tanks like it, who doesn't like it!?
Spellplague Guardians: Meh as a whole.
Malignant Growth: Does the target count as adjacent to the target? If so, this can get stupid. If not, then it's not worth it.
Contagion Flame: We can do stupid things with this and minions.
Echoes of Valor: WTF?! Stupid Pallys, getting all the love.
Metamorphosis of Spellflame: The damage increases each time they fail their save. Glass Cannons can use it to great effect, but that's about it.[/spoiler]
