Level 50
Many of us who have taken the time to master a crafting profession have come to the end and realized ... there's no benefit. No new passive, no special abilities, nothing of note.
To make Level 50 something to note, I suggestion three things: a nice title and achievement (counts as one thing); a costume sent via mail that reflects that profession; and a new passive.
For Blacksmithing, Woodworking and Clothier, the new passive ability is 'Multiple Traits', and allows players to put two standard traits on any item they craft (requiring the necessary trait stones). This does not allow players to double up on the same trait.
For Provisioners, the new passive ability is 'Artisan's Meal', allowing them to group a drink and a food together into a new item known as a meal, providing 90% of the bonuses of each for 75% of the duration, which would allow the stacking of many positive bonuses.
Enchanters get the ability to double up on weapon enchants, allowing two separate enchantments to be applied with the same stone, at 75% of the effectiveness of each (due to damage bonuses).
Alchemists find that they are borked once again, and do not get a level 50 passive. Just kidding. I don't know enough about the profession to make up something on the spot.
Master Craftsman
As a separate skill altogether, a Master Craftsmen title would be given to those players who have mastered four of the crafting trees (I pick four, because it is more than the three primaries that everybody takes, and less than the total, as I fully expect them to add more crafting lines later and it would create hazard for the achievements to constantly update the totals)
A Master Craftsman has their own skill line, which provides them the active ability to summon a crafting bench of each of the crafting skills they have mastered. Another ability offers a short boost to decon efficiency, giving better chance of returns while deconstructing.
Master Craftsman are also treated as such when addressing craft NPC's.
Master Workbenches
Seeded throughout the world in some of the most exotic locale's, these workbenches provide a new set bonuses known as 'Masterworked'. They require 8 of 8 traits researched, AND level 50 achieved in that profession. Unlike standard set bonuses, these workbenches are separate and alone, and often well off the beaten path, making them difficult to find and/or reach.
The Masterwork set bonus is a 3, 5, 7 and 10 piece bonus (10 if you count jewelrycrafting in future updates), that provides ... something awesome but balanced. Cause I haven't thought of anything myself.
Ruze Aulus. Mayor of Dhalmora. Archer, hunter, assassin. Nightblade.
Gral. Mountain Terror. Barbarian, marauder, murderer. Nightblade.
Na'Djin. Knight-Blade. Knight, vanguard, defender. Nightblade.
XBOX NA
Ruze is a veteran of the PC Beta, lived through the year one drought, survived the buy-to-play conversion, and has stepped foot in the hells known as Craglorn. He mained a nightlbade when nightblades weren't good, and has never worn a robe. He converted from PC during the console betas, and hasn't regretted it a moment since.
He'd rank ESO:TU (in it's current state) a 4.8 out of 5, loving the game almost entirely.
This is an multiplayer game. I should be able to log in, join a dungeon, join a battleground, queue for a dolmen or world boss or delve, teleport in, play for 20 minutes, and not worry about getting kicked, failing to join, having perfect voice coms, or being unable to complete content because someone's lagging behind. Group Finder and matchmaking is broken. Take a note from Destiny and build a system that allows from drop-in/drop-out functionality and quick play.