Within an about an hour of my bolting the neck on my Ibanez, I had already figured out how to play the C Major, G Major, D Major, A Major and E major scales using the low B string. About 2 days later, I'd gotten used to a lot of modal runs using the low B string and a bunch of 7 string chords and various arpeggiated stuff.
As Jbroll said, the trick isn't to view it as a 6 string guitar with an extra string.............view it as a 7 string, which is what it is, an instrument that opens up more possibilities.
It's not just an extra 4 notes, but you now also have another 22/24 positions (depending on whether it's a 22 or 24 fret guitar) to play with.
Play a 3 octave G major scale on a 6 string starting from the 3rd fret of the low E, and then, grab your 7 and play a G Major scale starting from the 8th fret of the low B string and you'll see what I mean. It is SO much easier to it on a 7 string, because you no longer need to make a stupidly large position shift to hit that G note on the 15th fret of the high E
I've never understood the "lower strings for teh brootalz" mentality. If I wanted low end chug and low end chug only, I would have just bought a fucking six string and tuned it down to B. But what I wanted was extra range.
To me, the 7 string is the perfect instrument for the soloist too because you've now got so many extra positions at your disposal. I use my 7 string for low end chug as much as I do 3 octave scalar patterns.