Hey, what can I say? Like all advertising folks, and even regular types, I’d often wanted to make some immediate changes to my website (an especially grating proposition pre-CMS tools.) But… even with a new site in the works, I would never consider having a “Coming Soon” home page for an existing agency (or any company for that matter.)
We should all be able to live with what we have for awhile (patience) or, if you really think that your website is underperforming to the degree that it might be pushing new clients away (and some agency sites I’ve seen do this) be innovative and come up with a simple creative solution that still assists agency branding. But, please, don’t run “Be Back Soon” as your lead message. There are lots of other agencies down the street that look very open for business.