Gotta throw in with agreement on prior threads. Stun is tough, but daze (in our game) has sit a little more comfortably. The few occasions when it was entered battle its effect has been about right. Denial of action, but not too much denial of action. That statement goes both ways as well, both for the situations where it has worked in the parties favor and when it has worked against them.
To try and so radically change it has alot of flow on effects. Alot of powers that use daze have niggly damage or effects otherwise, said powers will be made a far less attractive option. What about when daze is the consequence on a power (i.e. when you use this power you daze yourself), all of a sudden said power becomes hyper-good.
Focusing purely on your suggestion, there is an ocean on difference in efficacy between it an vanilla Daze. Im not going to tell you that my game experience is yours, but with Daze feeling so "right" to me, the impact of your change is, to me, too much.
If you find daze too much, might I suggest (and this is something I have been thinking for a while
* Daze = One standard action on turn
* Stun = One standard action on turn and grant CA