I just had a thought:
What is the relation, if any, between the power of a maneuver and for what the aspect can be tagged or how often it is GM-compelled?...
b) What is the difference, if any, when those aspects are tagged for effect by whoever applied them? Would the effects be stronger for stronger aspects?
c) How often do those aspects get GM-compelled? Should there be a difference in how often they are compelled depending on strength?
This is kind of fuzzy. You don't go by how much you succeeded on the roll to create the Aspect, you instead go on what the Aspect is and what it represents. I don't really see how you can Invoke for Effect on these Aspects though, unless you're just trying to bribe the GM to give a Compel.
These aspects get Compelled whenever the GM thinks doing so would add to the game. Applicability is what matters here, not strength. In general though you're going to be able to get more out of "Terrified Beyond Reason" than "Lost Confidence", barring an unusual situation.
In theory, for uncontested Maneuvers to place Aspects (presumably on the environment), the GM is already setting the bar for how powerful an Aspect is by setting the difficulty of the roll.
For contested Maneuvers against opponents, this becomes more tricky, and we have to return to the requirement that Maneuver-placed Aspects have to be things which an opponent can conceivably undo. "Twisted ankle" or "blinded" may be shaken off; "tied up" may be undone; "outflanked" can be outwitted; "disarmed" can be recovered. "Beheaded," "broken leg," "dead," and "sucking chest wound" are inappropriate Maneuver-based Aspects - though most of them are valid Consequences, but the target/GM gets to decide those (unless someone takes the Brutal stunt from the Custom Stunts thread).
So, generally, the Aspect is as powerful as you create it, and it is up to the GM to make it easier or harder to make it happen.