With 9.2.5 recently released the cost of leveling legendaries has been very significantly reduced. If you want to get into the market, now is the final chance!
With 9.2.5 the XP you get per craft was increased by 400%! So instead of crafting 15 legendaries per level, you only need to craft 3. This obviously dramatically reduces the cost to level a recipe. On my realm the top Blacksmithing recipes go from 150k per recipe to 30 000 gold.
Should you level recipes?
I think the answer here depends a bit on your realm population. On my main realm of Draenor, the profit margin is abysmally low for legendaries, on the note of barely 1-3 000 gold per item. On the other realm where I have some recipes leveled the profit margin is closer to 5-15 000 gold per item. I’d suggest comparing the profit margin on a rank 7 legendary by manually calculating the cost, then you can figure out how many you need to sell to make back the gold you spent leveling. If it is above 10 or 15 then you should start being cautious.
How long will the market last?
I expect legendaries to keep selling for the rest of the expansion. As long as players are playing, they will want max level gear. Season 4 might even bring some invigorated demand, but we will have to see a bit more about how season 4 will play out before we can really consider it.
Is it worth it?
I don’t have a crystal ball, so i don’t actually know. The lowered barrier to entry will mean more entrants into the market, so profit margins should be going down across the board. This makes going wide into multiple recipes even more important than it was.
Ultimately you will have to make up your own mind about this!, I can’t guarantee you a profit, and I expect the value to vary wildly between realms.