In any case, if you have a tailor with one of these recipes researched (or know one willing to work for tips), you can turn Windwool Cloth into blues, which you can turn into Ethereal Shards day and night. Each Ethereal Shard you make can turn into a fifth of a Sha Crystal (on a daily cooldown), three Mysterious Essences (no cooldown), or some of the most popular enchants in the game at the moment.
Speaking as someone who has sold thousands of Enchanting scrolls this expansion, I can tell you that the one material I never get enough of from disenchanting simple greens are Mysterious Essences. Until 5.2, the way I would make up the difference was by trading up hundreds of Spirit Dust I got from disenchanting greens I'd make with my Jewelcrafter.
The market is a bottomless pit for Mysterious Essences. Even if you don't want to sell scrolls, whoever is doing enchants on your realm will need a lot of them, simply because the most popular enchants tend to use more of them than they do other materials.
The availability of Windwool Cloth depends on the number and activity levels of players on your realm. It goes up on the weekends and after a patch, and down on weekdays as fewer people play. That said, historically on most realms, a stack of Windwool is a lot less than an Ethereal Shard, which is typically less than three Mysterious Essences.
You can also make 458 blue PvP gear with Blacksmithing and Leatherworking, however they're far less cost efficient, at least for me. Leatherworking recipes all take Magnificent Hide, which is worth a heck of a lot more than an Ethereal Shard, normally. Blacksmithing's cheapest recipe needs 8 Ghost Iron Bars, which comes closer, but is still generally more expensive than 20 cloth.
If you do decide to go the Blacksmithing route, the recipes that take 8 bars are:
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