Do you think Hydelean ever was seen by non echo users?

I was asked the other say if regular people could see Hydelean and I asked the person of they meant in the Aetherial Sea or outside of it. They then asked both. Which I said maybe inside the sea, but I wasn't sure about outside of it. And when I mean inside the sea I mean if some random person gained access to the sea and wasn't accompanied by an echo user, or an ascian.

I couldn't think of any time she appeared either as Hydelean or in her Venat form outside of the sea where only an echo user saw her. We also don't know if she showed herself more often in the earlier ages. Obviously if you're dead and are waiting for your soul to be cleansed you could probably see her.

At least a handful of people in Sharlayan.

They built 2 whole facilities that are used as dungeons that are based around reaching/talking to her and IIRC they only found out about the Loporrits and the moon and that whole project through her directly. Depending on how they built each of them and how they were run, it would've been more than just members of the forum since they needed researchers and people to build them.

As far as I'm aware, the only people with the Echo in Sharlayan were a few people in the Students of Baldesion.

I don't believe people whose souls were being cleansed in the lifestream would necessarily have seen her. She had no real involvement with anything outside of condensing aether into the mothercrystal and occasionally helping "chosen" people in the living world. She was buried deep down in the aetherial sea.

If we're talking about seeing her true form rather than just the Mothercrystal, I honestly don't even get clear evidence that anyone in Sharlayan saw her beyond just seeing the Mothercrystal. The Antitower and Aitiascope go deep enough to communicate with her, but I really don't get the idea that they ever managed to go deep enough to see more than she ever planned for them to, which basically means 'visions of the Mothercrystal' like we got.

This could seem a bit tenuous as evidence, but look at the actual Aitiascope dungeon layout: the fact those platforms exist at the start in the first place show they see value in having people stationed down there, and yet the Sharlayan platforms stop well before we get to Rhitatyn, let alone the Minfilia assist we need to get even deeper. Consider how far down we had to go to see her in the flesh, and that there wasn't even a path to get there before we did: do people think she was just flying freely around the aetherial sea for the entire time before we went down, and we just... caught her napping, or something? Because that's basically what would have to happen for Sharlayans to have seen Hydaelyn's true form, but for us to have to go that deep to meet her.

About Hydaelin's true form we actually do have references to no one having seen it, or at least no one who ever documented it. Her Unending Codex entry mentions the confusion of Her, the Mothercrystal, and the Planet by saying that people saw visions of the Mothercrystal with the voice of Hydaelin and equated one with the other while also equating Her with the Will of the Planet. As Cleretic mentioned above, Sharlayan might have been in contact with Her, but both the Aitiascope and the Antitower stop well before the Mothercrystal's even in sight, and while it's possible that Hydaelin Herself moved to physically talk to them, it sounds... unlikely.

Whether this means She was just conveniently out of sight from anyone contacting her, hid Herself inside the Mothercrystal, or whatever... who knows.

I do agree that if someone did go deep enough into the Sea Hydelean would still have done the whole "I'm a talking giant crystal." thing. I also don't think that she showed herself often as Venat or her true form outside of the sea. Or at least there is little evidence to say that she did.

It seems it's possible to be seen. Her other creations could sometimes be seen which makes their depiction in the real world super accurate. I'm sure an artist saw her and painted her image a long time ago but it never really became popular. She just doesn't inhabit the phantom realm so it's even rarer for her to be seen.