A concept for a new playable-race, with lore and feasability considerations

[Enkidoh]

It won't work, for one reason - the Echo. The Echo is such a major part of the narrative (and gameplay too for that matter) to ignore simply for the sake of adding a playable race that is incapable of using it. As the Echo is granted by Hydaelyn Herself (the Mothercrystal) to only living beings (because She is the source of all life on the planet), and the player's character gains it immediately upon beginning the game, needless to say an artificial automaton simply cannot be granted such a gift.

Personally I think we have more than enough player races in the game as it is - implementing the au ra into the narrative was a tight fit enough.

[LineageRazor]

As the Echo is granted by Hydaelyn Herself (the Mothercrystal) to only living beings (because She is the source of all life on the planet), and the player's character gains it immediately upon beginning the game, needless to say an artificial automaton simply cannot be granted such a gift.

This sentence contains an awful lot of assumptions. First off, who's to say that an automaton can't be a living being? What rule is there that there can only be life in things that are made out of meat? Secondly, even if they aren't "alive" how can you be sure that Hydaelyn can't grant the echo to a toaster oven if she so chose? How does being the source of all life limit her in any way in her interactions with non-living things? Hydaelyn is kept deliberately mysterious, and we currently have little or no idea exactly what she is capable of.

No, if there was an automaton race, players playing it would get the Echo, and there would be no conflict of lore preventing it - either the androids would be living things, or Hydaelyn can grant the Echo to whomsoever she chooses.

The biggest issue with this race suggestion is the OP's clear desire for an inhuman race. SE's made it pretty clear that they are reluctant to do this because of the difficulties in creating new armor models. If we did get androids, they'd be very humanlike in appearance, with only a few visual cues that they're actually robots - maybe some creases at the joints, or glowing eyes, or antenna or whatever on an otherwise human body.