This is going to be interesting for a couple of reasons:
Many of the features that we originally thought would go into Inscription appear to be going into Archaeology instead. So I doubt there will be anything radically new in Cataclysm Inscription.
Glyphs have never been tiered. There's no progression from a lesser stat to a better stat - each glyph does something entirely unique, and most scale with spells anyway - a glyph "gets better" because your other gear got better. While new/changed spells and abilities will occur in Cataclysm, it is hard to see how there will suddenly be hundreds of new glyphs added. Unless large numbers of old glyphs are retained in spite of having no purpose (like the Warlock Glyph of Souls - a spell for which mana is irrelvant, because it isn't used in combat).
Inscription was poorly balanced relative to the rest of the economy. Not only the low demand for glyphs compared to the ease of making them. But also the way Old Azeroth herbs were just as likely to be required for a "good" glyph as Northrend herbs. Lack of flight in Old Azeroth meant that auction prices for low-level herbs could be higher than Northrend-level herbs, which never fitted the logic of the rest of the game. The Ink Trader leveled prices, but ultimately just diluted the herb economy, by making all herbs rather similar (for Scribes, at least). That could be addressed in Cataclysm, which is logically a good opportunity to rework pre-expansion elements of professions.
Lastly, the role of a minor glyphs could be reviewed. I know for a Warlock, it's a real struggle to fill 3 slots with anything that even sounds like it might be useful. In contrast to (depending on spec' and role), some major glyphs we are more-or-less game-changingly essential. Minor glyphs could become more like diluted versions of major glyphs. Or they could become entirely cosmetic.
