Alright so I absolutely love this game, Been playing since release on Xbox and had the game purchased on PC since release, however there seems to be something missing in individual character progression.
Right now pre-DB you get a character to Vet 16 and you're done. Aside from Crafting, (researching) there is not a whole lot that is keeping me wanting to come back and play every single day as there was before. I believe that the content has gotten stupidly easy, and the feeling of progression has been taken away significantly. So, this is what i propose.
DISCLAIMER
I understand that this would take a long time to implement correctly, and that the balance and numbers I will suggest within should be taken simply as ideas and not as what I think should be completed items.
First off, these "Legendary items" would take up your weapon slot, You would have the choice to double bar it or single bar it.
They would have a sort of infinitesimal scaling to them, allowing for them to be upgraded beyond "gold legendary"
The weapons would have levels given to the quality that they currently are. For this example I will call the Weapons level "Legendary #"
A Legendary 1 weapon would currently be equivalent to a Vet 15 Gold weapon, with its extra bonuses. With the removal of VR ranks consider this artifact CP Rank 150, this could scale all the way to CP cap, and would be the only item in the game for each class that can scale in such a way.
Ideal requirements for receiving your legendary weapon. (OF course this is not a thorough list, I want it to be something to work towards, and not just have everyone have it day 1. It would probably need a more significant PvE requirement, however the only one I can think of is Tamriel Hero/Explorer. )
Must be Max Rank (Level 50) duh.
Must have all of your class skill lines maxed.
Must have completed your original zone with "Alliance Hero"
Must be at least an alliance rank of General to start the quest to receive the item.
Must have an Undaunted of 9 and have all the "Veteran Dungeon Achievements" and Normal Dungeon Achievements.
Must complete all of the Achievements for "Dark Anchors"
Attaining this weapon would NOT require the purchase of any DLC as it should be a base game update. However gaining new achievements can allow the upgrading of the weapons in the future. The weapon would be Bound To CHARACTER. Could not be banked, sold or traded.
Each class has 3 different specs for each weapon. a Healing Spec, A Damage Spec, and a Tank Spec. You may only own one of the three at a time, Choosing a specific spec would not tie you down to it forever, you could change it, however, when swapping between specced artifacts, you lose all current progress towards the next upgrade. The levels could never go down though, If you have a Legendary Rank 3 Healing staff, and you are almost to 4 but you decide you want to swap to a Tank spec, you do not start back at level 1, instead you lose all progress you have towards level 4.
Now the fun part in imagining how this could work for each of the classes so that it is somewhat balanced. (at least in my own mind) All Percentages should scale with the level of the weapon as a whole, so if it is 2.5% base, at level 2 it could be 3.5% or maybe 4.0%. incremental improvements but adding longevity to investing in that particular character.
Nightblades
Damage Spec. Would increase the damage done by the skill Veiled Strike (and its morphs) by 2.5% and adds a bleed over 10 seconds for the amount of damage that Veiled Strike's current tool tip states. While equipped the effect from Refreshing Shadows is increased in increments of 3% based on the weapons Legendary Level.
Healing Spec. Increases the Damage and Healing given from the skills Strife (and its morphs) by 4%. Funnel Health morph once again grants healing to yourself and 2 other targets. Swallow Soul now has the additional ability to heal one other ally, and has the Vitality increased by 4%. The Soul Siphoner Passive is increased by a total of 3% (scale able)
Tank/Mitigation Spec. The ability Blur and its morphs now also provide 2400 Spell and Physical Resistance as well as increasing the dodge chance from 20% to 30%. Resistances scale, Dodge chances do not. The weapon also passively increases all recovery by 3%. While equipped, using a class ultimate grants Major Protection for 12 Seconds, and Grants Major Vitality increasing healing received for 12 Seconds.
Templars
Damage Spec. Increases the damage done by Puncturing Strikes and its morphs by 2.5%. Also grants 6 ultimate (every 4 Seconds) Upon activation. While equipped the Burning Light passive proc chance percentage is increased to 40%. Ultimate gained and Damage Percentage scale, Burning Light chance does not.
Healing Spec. Increases all healing done with class skills by 3%. Once an hour, upon death, Call upon the Aedra to resurrect downed allies (in your Party) within 12 meters, and healing your allies (in your party) to full. Can activate this ability with a synergy for up to 3 seconds after death. As the user you can choose when this effect kicks in. Not just automatically. Note: In PvP zones this ability is restricted to a maximum 12 players.
Tank/Resistance Spec: Rune Focus and its Morphs now also provide 225 Stamina per second for standing within the Rune, or for 8 seconds after leaving it. Also increases the effect of Major Ward and Major Resolve by 10%. (5280 base is increased) While standing inside a Nova, Dragonknight Standard, Bolstering Darkness or Negate Magic, Decreases block cost by 8%, increases your damage by 8% and increases healing received by 4%. Does not scale.
This might be OP as hell but its what I could come up with.
Sorcerers. This is going to be the hardest one to take both Magic and Stamina users into effect with the lack of Stamina costing Damage abilities for Sorcerers. At the moment I am going to simply hope that C-frags gets a stam morph at some point in the future.

Damage Spec Crystal Shard and its Morphs now do an additional 2.5% damage and have a 10% chance to proc an elemental effect on the target. The Disintegration passive can now proc at 15% health and has increased damage by 35%. (Does not scale)
Healing Spec; Increases all healing done with class skills or class passives by 3%, Healing from pets is increased by an additional 4%. Overload Light Attacks now have a 4% chance to heal an ally for 50% of the damage done. While a pet is activated gain Major Mending for 3.5 Seconds.
Tank/Resistance Spec. Reduces the cost of Encase and its morphs, and Lightning Form and its morphs by 30%. While an ability from all 3 class skill lines is slotted, Stamina Regenerates while blocking at a 50% rate. (example if your recovery is 1200. while blocking instead of receiving 0 stamina while blocking. you gain 1200 every 4 seconds, instead of every 2 as standard). While this weapon is slotted reduces the cost of all class Ultimates by 20.
Dragonknights.
I am not very familiar with how the DK's play as a whole so I am not qualified to even give an opinion on what should be used here. I have only ever played one DK and he is still not even Vet rank, so If someone else wants to take the time to put something together that is in the similar format at the above I will be sure to include it.
Finally, Leveling up the Legendary Weapons would take a lot of time, and would be the final end game piece for every build ideally. I think that the leveling of the weapon would ideally have a UI similar to that of the Caldwells Almanac in that same section of the Menu. In my opinion it should take 4-8 weeks to upgrade a level on a weapon by consistent game play, (10-14) hours a week.
Some ways to advance the level of your weapon might be, Appear on any leader board 4 times (at the end of a cycle), and gain rewards from those events. PvP or PvE. Earn x amount of Alliance Points or a reduced number of Tel-Var. Complete all of the current trials on both normal and hard mode. ( would include checklist of trials and mode completed on)
Each event would be given a point value. And upgrading a weapon requires a certain number of points to actually upgrade it. This way PvP only players can earn their next upgrade by simply gaining AP and TV stones, however they could potentially earn it faster if they were to do end game PvE and vice Verse. PvE players can potentially never have to go back into PvP zones however it would be much quicker to complete the level by doing both!
Things like Becoming Emperor, Holding a #1 spot on a weekly leaderboard, Holding Emperor for an extended period of time, would all have increased amounts of points. However Holding emperor would have diminishing effects simply because of the possibility to abuse this system. Becoming Emp could only be counted once per level, To avoid Emp trading.
Alright I think that's about All i have for right now. Its long, probably some bad grammar in there. But if you made it all the way through this thank you for your time please leave comments on what you think and how you would see something like this holding attention and gaining popularity.