I have a feeling most of you would push the "ROCK" feel, as I definately would. As much as I absolutely adore each of the praise albums, it's time to stick with rock.
Personally I would bring back the keyboards for maybe half of the songs to give the album a bit more variety in sound. With Jekyll and Hyde, their were too many blank spaces to be filled for my liking (just my opinion). The keys don't necessarily need to go on tour, but for the studio album, I think it's a must.
I would be advising on the songs to have a bit more length about them than Jekyll & Hyde with some, no, lots of Bobs' guitar solos with a couple of songs containing instumental interludes like on Last Daze and the Medley at the end of Petra Praise 2.
I would bring back the "old" formula of having 2 or 3 ballads (at least one with a praise emphasis and one with Bobs' acoustic guitar genuis as shown in Grave Robber and Fools Gold etc) on the album as we all can say that we have been blessed by them in the past no matter how much of a head-banger we claim we are. The rest would be pure rock with a real hard edge, with styles along the lines of Midnight Oil, Jekyll and Hyde, Hit you where you live etc, apart from one, which would have a rock/praise feel like Somebody's Gonna Praise His Name or Creed.
For the album cover I would push for a new millenium style flying guitar incorporated with the band members to be on the front in one of those cool group photos like ones from the This means war! and On fire era (that point could be on a thread of it's own - I know many fans have different opinions on the old flying guitars and band members being on the cover

By the way, there have been reports that Petra might be doing a live album next. Any thoughts on what you would do with it? Some new material released live maybe??
Have fun with your ideas

Remember, this being only hypothetical, we are sharing what we would desire in our hearts, not trying to dictate to Petra what they should do. Who knows, it may be your ideas that inspire them to go in a certain direction.
God Bless!