Speculation posts are always dicey, but the best ones make you think about how and why things work. Today, I'd like to talk about crystals - those rare-ish enchanting materials you usually only get from disenchanting epic gear. In Mists of Pandaria, Enchanters were given a daily cooldown where five shards could be combined to make one crystal once per day. This helped circulate more crystals. It also helped that the enchants that used the crystals were gated behind a reputation grind - allowing some supply to build up.
This was in contrast to Cataclysm, where crystal enchants were purchasable using shards as currency on day one. The dungeons, and the raids proved to be more challenging than Mogu'shan Vaults - and with no LFR, the amount of spare epic gear, and thus, crystals, was very sparse. So we understand how the availability of crystals has behaved in the past at the launch of an expansion. And we also have a good idea of why.
In Warlords of Draenor, we will see many changes. But, as far as Enchanting goes, we've already seen a fair bit of changes. The upconversion and downconversion of materials has helped a lot. The scaling of enchants has also been another change. There's certainly room left for further changes, but I doubt we'll see anything revolutionary - to do something like that so soon after re-vamping a lot of the profession would just seem like a waste of effort.
But enough preamble - the point of this speculation is that I think that, at this point, crystals will be less available in Warlords of Draenor's early days than they were in Mists of Pandaria's. With Normal and Heroic raiding both allowing the Raid Lead to choose whether to adopt a LFR-style of loot or a more traditional style like Master Loot, many will invariably choose it. The allure of this option is that it bypasses loot drama, and ensures that loot that drops is at least usable by someone even if it isn't an upgrade. The downside is that there will be less extra loot that isn't needed - and gear that drops that isn't needed will be soulbound, and won't be able to be disenchanted by another member of the raid - as with Master Loot.
There are of course, potential work-arounds to this that Blizzard can build into the game design. And if we see those, we'll have to take another look at this. But all else being equal and going off what we know for sure via blue posts and tweets about the loot options for Tier 17 raiding, I expect that crystals will be more rare in the early days of Warlords of Draenor than we've seen in Mists of Pandaria. Plan accordingly - keep your eyes open for new info.