Back in the dying days of cataclysm - snowfall inks were ... considered vendor trash by most (other) bloggers. I had decided to stockpile them - being slightly contrarian in nature. It has stood me in good stead - at least where snowfall inks were concerned.
However, I didn't pick the real value in snowfall inks - northrend inscription research. At the moment, snowfall are still needed.
JTMC covers some details of glyphs changes, but this almost irrelevant to me. There will be changes to glyphs, so some glyphs will sell better for a time. I will learn the lot, and post any above my threshold, as usual. (Though I will have to make 1/2 an effort to send new glyphs to my horde toon).
However, assuming that the new glyph is northrend research based (it is on the PTR), there should be a run on snowfall ink and/or northrend herbs (capped by the cost of 10 blackfallow -> 1 snowfall). It won't be a huge run as only dedicated scribes will bother learning it.
If the glyph is 'book' based, then the availablility will be much lower (i.e. higher prices); trainier based and the glyph will be junk value. However, I don't see any reason why it would change from it's PTR research basis.
Tonight, I checked on my snowfall stocks.
Genetic Testing Results - [image: That's very exciting! The bad news is that it's a risk factor for a lot of things.]
13 hours ago