The thing is, Astral Wasp is just not a very good spell. WOTC printed a few "choose your poison" spells, which tell an enemy to not take a certain action, or they'll take damage. "Don't move or you'll take damage" is a form of control. The place where they messed up, however, is that the extra damage is too low. "Don't move or you'll take 3 damage" is not control, because monsters won't care about the 3 extra damage. Astral Wasp basically turns you into a poor man's striker.
(you can very well play a wizard as a striker, but the key to do that is to use area effect elemental damage, plus either Elemental Empowerment or the Tiefling's boosts to fire attacks)
Note: don't get too caught up by -2 attack penalties. They're nice to have as a side effect, but they shouldn't be your main goal. Why is that? Because exactly 90% of the time, they do nothing (the monster either still hits, or would have missed even without the penalty). This means that Psychic Lock is good, since it stacks attack penalties on top of what you're already doing; but Chill Claws is not, since the minor penalty is all it does.
Sorry, but this is so wrong. If your encounter spells aren't providing control, you've picked the wrong ones. Grasping Shadows is control. Color Spray is control. Twist Of Space is control. The list goes on, and all of those benefit from Enlarging. There's generally very little reason to take an encounter power that's not an area effect (except if you're an enchanter).Hence, since most of your control is coming from Daily Spells, Enlarge Spell will sadly do very little for the controller style wizard.