This is the way Marketo works. In way way it's quite helpful as it forces the user to review the logic before activating it. In your case, however, sounds like a bit of an inconvenience. May be if your scenario allows you, you could schedule a re-ocurring batch campaign (making sure that you did change the members and the email content before it's sent again).
Hope this helps!
Hi Macarena Lopez,
Thank you for a quick response.
I think a good middle ground solution would be the ability to mass-approve smart campaigns in some way. A couple of related ideas:
Voted up to all three