Well, with Bethesda you can never be too sure.
Exactly the opposite of that, in fact. When the storytelling is deep and layered, you can never be too sure. But when it's stale, predictable, childish, and simple, it's very, VERY easy to be sure.
But yeah, Amata does at first come off as a love interest, but later in the game it is made more apparent that she's more of the "best friend, your still in the friend zone" kinda shit.
I never viewed Sarah Lyons as any kind of love interest though. Especially since she pretty much dies (or falls into a seemingly un-fixable coma), which was kind of like fucked up sense of humor on Bethesda's part. "Here's your best friend. Love interest? Nope, Friend Zone mother fucker. Here' Sarah Lyons. Love interest. Yep. For awhile anyway, until she dies/gets put into an unrevivable coma before she can become anything close to an ACTUAL love interest."
I really never saw what the "Amata romantice character" supporters fantasized, because she was NEVER depicted as more than a friend in the game. Not later in the game, not earlier in the game. Never. When you have the option to comment upon being woken up by Amata shortly before fleeing the vault that you had been dreaming about her, she's disgusted by the notion and asserts that now's not the time for jokes. There are no other alternatives in her response. There's no circumstance on the lone Wanderer's upbringing decisions that may lead to her being receptive towards the character in any fashion other than friendship. The closest she ever comes to being romance material is the role played one-sided affection that's totally anchored in the player's silly mind, not found anywhere in the game.
But as for Lyons, she's hardly out of commission for very long, unless you take your sweet-ass time doing fuck all at the opening of "Broken Steel" before completing it. Regardless, it's like I said, that period is her character undergoing the "tragic loved one" arc of her character's evolution. You have that touching moment when one must be sacrificed, and when you come out of your coma she's unconscious too, and it looks depressing and bleak. Then once your mission to save the day reaches its climatic conclusion, lo and behold Sarah Fucking Lyons shows up, right as rain, to take you back to safety, and in the epilogue she reveals totally candidly that she feels very strongly for the Lone Wanderer, and wistfully wishes that their circumstances had been a little different. Barring a Bioware-esque romance subplot, that's the closest a game like this ever WILL get to 2 characters falling in love. This is all, of course, contingent on the player not making the most bastard-evil of choices, mind you. No "fuck that, I'm not going in there, you go sacrifice yourself" or targeting the Citadel instead of the walker, etc. It's still a definitely love interest, albeit a simple and fairly one-dimensional one. Again, with Bethesda, you really CAN be too sure.