You jumped in a summer book. Meaningless. Did you make a Bonus?
Rather than evaluating the viability of the format in general, it might be best to assess the
station specifically.
I am not surprised the Zone made a leap in the last book. Look where they were before. They almost had nowhere to go but up. Nevertheless, that is insignificant compared to the positive changes they've made in their music, imaging and programming.
Sure, they've made adjustments to their lineup but the "personalities" won't make or break them. Though it's good that they are finally being consistent with timeslots, this type of station succeeds first and foremost because of it's music. It's like that with
any music station... as much as the jocks hate to hear that. However, I must say that most of the jocks now fit the style of the station and are "listenable". They (with one or two exceptions) finally complement the station.
Thanks to these old radio ears of mine, I could hear the changes immediately - and not merely because they changed a positioning statement (again!) It was obvious that the playlist was becoming more focused as they were finally defining their format. They backed it up with imaging explaining the format, though it gets old quick and someone needs to tell them to freshen it up again. Furthermore, they are participating in events that give them credibility in the format they have adopted. (It's always so annoying to see a radio station at the concert of a band whose music they don't play.) In a nutshell, the station is much more solid that it has been in years.
If the new PD continues on this path I'd expect to see continued strong performance by the Zone. I have no current affiliation with them so this is just my objective 2 cents.