One thing that's always been true of glyphs, no matter what their incarnation, is the fact that they're class-specific. I think it would be interesting to see that change, if not for major glyphs, then at least for minor ones. There are certain aspects of the game I would love to have the option to modify, just a little, for quality-of-life reasons. There are also abilities that were once available that no longer are, which could be reintroduced via classless glyphs, useable by all. Here are some generic glyphs I would love to see.
Mount speed glyph
Back in the day, there were a couple of really convenient trinkets that, when equipped, gave you a boost to mount speed. They were the Carrot on a Stick and Riding Crop. I have particular fond memories of the Riding Crop because it was one of the few things I could make, as a leatherworker, that routinely sold for gobs of gold. With the release of Wrath of the Lich King, the functionality of both trinkets was reduced, and eventually the Carrot on a Stick was removed entirely. Considering that old-world flying has been available for a couple of expansions now, and people get around a lot on their mounts, I would really love to see another way to gain a boost to their speed. A minor glyph would be the perfect way to do it.
Mount up speed glyph
This may just be my druid flight form roots showing, but it would be really nice to be able to hop onto a flying mount (or any old mount) just a tiny bit faster. This certainly isn't a necessity, but for anyone trying to farm a lot of herbs or ore -- especially at lower levels, when you don't have access to your Pandaren farm -- this kind of option has the potential to be really helpful. And maybe even make those flight-form herbalist druids just a tad bit less infuriating.
(For the record, everyone, my druid is a skinner.)
There are macros and addons that will randomize your choice of pets and mounts. You can set them up to drop an algorithm-chosen pet whenever you land from a taxi, or click on a button that will grab a random mount from your library whenever you want to gallop off into the Azerothian night. Wouldn't it be cool if there were a glyph that let you do the same to your hair?
I like the barber shop, but I don't like it nearly as much as some of my friends, who change their characters' looks all the time. I think there's a definite population of people who would love to have a glyph that randomized their character's hair color and/or style every time they loaded into a new area. I have no idea how possible this would be within WoW's software architecture, but it's certainly fun to think about. I'd probably use it, at least for a little while.
Animation effects glyphs
The Path of Illidan was an item you could gain from an old loot card in WoW:TCG. It was pretty popular in its time, and it's easy to see why. When you redeemed it in game, it gave your character little green fire footprints for a while, and it looked really neat. I'd love to see some kind of minor glyph that did something similar -- maybe not the exact same thing, at least for the sake of the egos of those who may be hoarding that particular loot card. But what about a trail of blue fire? Or shadow flames? Or plain old red fire?
Or what about other types of fun animation effects? You could leave a trail of sparkles every time you swung your weapon! Or if sparkles aren't your thing, some sort of flashy light effect. Maybe we could have little clouds of dust left swirling behind our ground mounts, with puffy white contrails for flying mounts. Or a shiny ping on the blade of an axe or polearm, similar to what you get on your character's teeth after using the Tooth Pick. The possibilities are endless!
Sound effect glyphs
In a similar vein to the above, but instead of visual effects, maybe there could be sound effect glyphs to spice up your characters' abilities. It might be cool to change the noise your weapon makes when swung, or your spells make when cast. I don't know if there's quite as much potential for sound effects glyphs as for animation glyphs, but I'm sure there are plenty of options out there, nonetheless.
I think generic glyphs could be a nice addition to the game, not only for reasons of quality of life or as further ways to customize a character, but also potentially as a way to help out the inscription profession. Perhaps having glyphs that are useable by all characters could help inject some life into the flagging glyphs market. I don't know about you guys, but on both of the servers I regularly play on it is nigh-impossible to sell glyphs. If there were some glyphs available to everyone, it might help move things around just a tad bit more.
What about you, readers? Would you be interested in any of the types of glyphs mentioned above? Why or why not? Have I missed something that you would really love to see? Let us know in the comments! I look forward to hearing your ideas.