Maybe I'm reading it wrong, but this just looks like a power card generator. I'm looking for guidelines for designing balanced powers of given levels.
As far as I know, there are no such guidelines.
The way to do it is to look at the other powers of the same level - and post them on boards to have eager enthusiasts tear... I mean
critique them!
The big, big
big thing to remember is that balance matters only at the table during play. In other words : if you create something that would be completely broken when combined with Y but your table doesn't have Y, then the point is moot - your stuff isn't broken at your table.
There is a
huge difference between making a homebrew thing work correctly for
a campaign and making something to "add to 4e for everyone" (as a
Dragon article for example.)
As an example:
- I gave a player a "cursed abyssal staff of ruin" :
every time he casts a spell (he's a warlock), he takes 3 damage and deals +9 damage. - That is completely bonkers on it's face! But in this game, it works - and the player
still manages to under-perform... (he legit rolls 8 or below on d20 rolls 90% of the time!)
- In the same campaign, I gave the swordmage a boon that basically copies the Runepriest's healing power. That's also bonkers! But again, in
this campaign, with this group, with these players, it works!
None of this is to mean that anything is a good idea - but it does illustrate the point that 4e is fairly resilient.
TL;DR - you can probably eyeball it.