Over the years World of Warcraft has had a creeping adoption of a mechanic whereby you discover new recipes for a given crafting profession via a daily recipe. One of the first was Alchemy in the Wrath era, which had Northrend Alchemy research.
Up to this point all professions followed the basic pattern of training new recipes for money at a profession trainer. There were rare drops of recipes from world creatures (meh) or as an object to pick up in dungeons (yay!). I am biased in favouring the explorer-style model of finding rare recipes – you could go into Blackrock Depths and find specific engineering and alchemy recipes by clicking on a “hidden in plain sight” item. Random drops from creatures in the world (e.g. jewelcrafting trinkets from creatures in certain Cataclysm zones) are ok but though it can be annoying effectively having to grind random creatures to get them.
But the daily cooldown recipe approach locks crafting progression behind a pernicious RNG barrier with a timer. This was repeated in Mists with the random recipe procs from potion manufacture recipes though without the strict 24 hour timer. There are other examples in game as well, for instance the facets of research for jewelcrafting or the scroll of wisdom for scribes. Personally, given how easy it is to make money in the game, I’d much rather see the recipes on the trainer and be able to buy them as I chose. Looking at the untrained recipe list was always part and parcel of the excitement of leveling a profession, part of the motivation to keep leveling to the skill cap.
Certainly it does draw out the process of learning new recipes over time, but then why is this actually necessary? Perhaps this it is just part and parcel of Blizzard’s recent allergy to having NPC trainers for anything in game?