Very instructive.
The big fat killer of most instrumental stuff is the lack of hook. It's what killed the shredder 80's for me. Loved the playing but I'd rather listen to AC/DC Hells Bells any day. It's had a big fat hook.
Thing is Randy, you have a point; the answer is not to 'shred more' and it clearly is not. I think moreover, Slipin (not to put words in his mouth), was focused on the hook.
Given the example of 'The Key'; the song was good. Nothing to be ashamed of at all. The real hook in the song, the opening riff was not fleshed out in the song.
If I'm giving a real critique, and to maybe lend some creedence to my thought, I've been around the business a lot. I made a living understanding what people wanted to hear.
While you will have shredheads, few people want that. That, Randy, was clearly your point and you were spot on at that.
Returning to 'The Key', it was melodic but it did not really center around clearly defined themes. The point of the Recording Revolution post was that to really grab a listener, there has to be an identifiable hook to grab the listener.
This is what you hear in Johnson's Cliffs of Dover, Lynch's Mr. Scary and even Edgar Winter's Frankenstein. Even Steve Stevens Hellcats Take the Highway, it drives back to themes that are engaging and exciting to the listener.
Without the returning theme, a song meanders. 'The Key' was melodic and had a theme but a theme that itself was not fleshed out and was subverted for the lead playing which did not really revolve around a theme either.
Not to beat down but in your blog post, you lamented the shred instead of melody' deal was an issue but in the end, neither is really wrong or right, it is hook. If you want to grab and audience, return to that riff or lick that smacks the listener in the chops.
Going back the 'Hellcats' song, even in the lead playing, it had a method. You'll notice that it just wasn't lead playing but leads that were used to build tension with ascending themes.
Just some thoughts. I had to talk a lot of music to folks in my day and it usually boils down to something very simple. Hook.
