I think this, as a request for a Legendary Armor Precursor that is not gated by Raid, WvW or PVP, is valid.
A legendary armor is a convenience equipment. It has similar stats as that of an ascended armor and besides the skin (for PVE) the benefits to having a legendary armor over having its equivalents are (i) inventory space; and (ii) free change of stats, runes, infusions. These benefits have multiplier effect with the introduction of Legendary Armory - that is more inventory space across multiple characters and access of free-stat-changing-armor across all similar armor-type characters. As such, it is not a needed in any of the game content besides the cost and time efficiency of having one to theory craft, study, or tweak one's stat.
When the Legendary Armor was earlier introduced, for me it was like the ultimate end-of-game item. This was not true anymore when a Legendary Armor for WvW and PvP was added. These types somehow provided the players who don't play or cannot stomach the PvE content to gain access to a LA Precursor and a Legendary Armor.
Since not all PvE players play WvW, PvP, or raid, how about providing a means to craft a LA Precursor and a Legendary Armor that is not gated by those mentioned game modes?
Options that may be reviewed to implement this includes a quest to be able to farm higher-end materials on existing nodes towards crafting LA Precursors.
For those who don't wish to take such path, nothing is lost. However, for many PvE players who don't do raid, it may be an exciting content to spend and waste one's time in the open world.
Other benefits may include lessening the number of players being forced to play specific game modes just to earn specific LA Precursors. This may lessen the exposure of and prejudice to players who are doing game contents that they are not comfortable with – which somehow contributes to making specific game mode toxic and not fun-to-play anymore.