OK, so if you've been reading this blog for any amount of time, you'll know that I'm not the biggest fan of PvP. I only ever PvP in order to gain gear for my PvE activities, and even then I only do it grudgingly. For the most part, my dislike of PvP stems from my opinion that the BGs are not fun, mostly because of the incompetent and loudmouthed morons who make up the populations of both Alliance and Horde BGers.
In addition to staying away from PvP due to the morons I'd have to deal with, I also avoid it because I like to save money. Serious PvP requires specing for PvP, and specing back and forth from PvP to PvE could cost up to 100g a week if you swap specs twice a week.
Rumors from Blizzard, however, point to some sort of system that would make respecing either easier, cheaper, or both. For the sake of argument, let's just assume that you can now have two saved specs that you can swap back and forth at will and for free, essentially removing the cost of switching from PvE to PvP. What barrier is left, besides gear, between these two play styles?
Inscription. Each character has six glyph slots; two lesser glyphs, two minor glyphs, and two major glyphs. The power of each glyph is based on its type. Major glyphs will have major game-play implications, while lesser glyphs will be cosmetic or convenience based. Unless Blizzard only creates a very limited number of glyphs per spec, forcing everyone of one spec to obtain the same glyphs, there will be glyphs that are superior for PvE and those that are better for PvP. Swapping glyphs will be the new barrier between PvE and PvP.
This could work out in a few different ways. First, Blizzard could keep glyphs as they are, and those who were serious about their PvE to PvP swapping would have to pay to reglyph. Glyphs could either be expensive, and intended to be permanent (as long as you stay the same spec), or cheap, making reglyphing a slight inconvenience, but not that bad. Cheap glyphs, however, make it seem like Inscription will not be a very profitable profession, though a full judgment as to Inscription's money making potential will have to wait until release.
The second option could be that Blizzard would implement two glyph tabs that could be swapped back and forth. You would still have to buy all of your glyphs, but you could have one tab for PvE and one for PvP. This idea could also apply to having different tabs for different specs.
I'm not sure which is the best option, since this not only has ease of play implications, but also economic implications for the herb market, and profit implications for Inscribers and Alchemists. Blizzard needs to think long and hard about how much of this game they want to be PvP focused and how much PvE (though the creation of Lake Winterspring, new BGs, and the mostly PvP focused 51 point talents makes it seem like PvP is their focus). If Blizzard wants to have their cake and eat it too, they need to make it simple and easy for players to swap between their PvP and PvE gear, talents, and glyphs.