Mengu -> Force Daggers' strength is in its flexibility. Use it as a blast for 2[W] on several foes, or place it on a single enemy for 5[W]. And rolling 5d6 (brutal 1) plus Cha and Spell Source damage yields a result on par with other single-target spells of the same level.
As for the power levels, I determined what levels I wanted to cover (basically, every heroic spell level), and then looked at every single sorcerer spell of that level, plus a couple of rogue and warlock powers. Only one spell was changed from the original draft, from 4[W] to 2[W].
The article was aimed squarely at making a "melee arcane striker", and the sorcerer already had Sorcerous Blade Channeling going. The [W] spells offer an interesting choice to the player: use a dagger for its sorcerer-only enchantments or superior implement properties, or take a feat and use kukris or katars for brutal 1 or high crit? Imagine an epic sorcerer with a vorpal kukri (where every 1 is a reroll and another shot at rolling a "6")!
A sorcerer that chooses for the latter has the possibility of multiclassing or hybridizing into melee classes. Cosmic and Dragon sorcerers should look into Barbarian and Paladin powers, while Storm and Wild sorcerers should look into Rogue powers. Of course, Bards have lots of weapon powers that a melee sorcerer might want to look at (self-healing and self-buffing rounds them out nicely).
I'll ask if I can share what Dragon Blade Channelling did. I don't know why it was cut (along with an Epic feat).
All that said, I welcome all opinions and suggestions so future articles and books are improved.
After this, my next writing will be seen in Heroes of Shadow.