That quote from Nojima has nothing to do with her Cetra responsibility. Nojima was talking about a relationship. So when he said Aerith has a big burden/responsibility (負担), it means she's the one who often tries the relationship to work.
So what Nojima means in that interview wasー both CT and CA has their own problem in their relationship. CT has a problem with marriage/love/family premise such as communication. CA probably would have no such problem, but Aerith would be the one who "work hard" in the relationship. And we really see it on Rebirth, it's always Aerith who makes a lot of effort in the "date". I wonder this is what makes her realize that this is not what she wanted. Her and Zack is balance, just like Cloud & Tifa; relationship works because two persons make both effort.
Zack balances out Aerith's gremlin energy for sure and they both have a push and pull that works great for their tandem.
What's interesting to me (and I think people with eyes and ears who have played Rebirth) is showing what you just said here, how much effort Aerith has to put in to get even remotely anything out of Cloud. The Gondola date and Nibelheim being two examples, both times she pats the place next to her and Cloud is having none of it, on the Gondola date I actually felt a little bad because he has a face like a smacked ass half the time and barely looks at Aerith, it isn't until Aerith opens up a little does he start to engage, even then she basically has to latch onto his arm for anything and it's like come on Cloud -- yeah I'm a CT person but even i'm saying out loud give the girl something like she clearly needs a little comfort here at least -- and in the end he delivers. But there's many instances of this where Cloud really needs to be pushed to open up to Aerith at all, this continues on into the Sector 5 date and then in the Church where she's clearly opening up and, I supposed depending on HA or LA Cloud will engage a little or not engage much at all, even when she's saying she likes him, he just says she's acting weird. I couldn't believe it in Rebirth at times.
Contrast this with Tifa and even though he gets shy and awkward it's a hell of a lot more natural and comfortable? Or rather it progresses that way where they have a stereotypical "lovers tiff" from the start of the game up until the last couple of chapters where they had Aerith take over and Tifa's voice started to get drowned out by Sephiroth (as he said in Gongaga). But you can actually see realCloud come out a bit in Gongaga during their conversation where they nearly kiss. But let's also contrast the Gondola date where Tifa doesn't try to get him to sit next to her, he's stares at her like 3 times and seems like he wants to say something but can't get the words out, and when Tifa closes in on herself and seems unsure of what she is feeling is mutual, Cloud actively reassures her and initiates rather than having to be pushed into it.
What's interesting is you bringing up Nojima's quote about communication... well with the OG I think everyone would agree with that, but after Remake and Rebirth? You can actually see the developers making an active effort to get these two to actually communicate more through their issues and because of this what you got in Rebirth was "Romantic Tropes 101" development from start to finish, a much more fleshed out relationship building where they try to express their feelings to each other (not always necessarily romantic) and if P3 goes the way of Disc 2 in the OG it makes the relationship potentially a much richer one than it was in OG and makes much much more sense in terms of natural progression.
I'm reminded of what Nomura said about fleshing out Tifa herself and her relationship with Cloud in Rebirth so that we'd see their growing feelings over a natural course of the games and it's delivering in spades in Rebirth. Any OG players would not have even guessed we'd get the romantic drama, angst and tension they got in this game.. Tifa confronting him from the off? Cloud initiating a kiss? Insane.. and you figure they have to top this in Part 3, I don't see how it's possible for them to walk back all the domestic and human relationship building between Cloud and Tifa that they have done in Remake and Rebirth, the kiss seen round the world, people celebrating FF7's first kiss after 27 years. How do you walk this back in P3 now to make Cloud and Aerith canon? You'd have to to really rip up all the narrative structure and character building you've done in the first 2 games, you have to make Cloud somebody who would trample on Tifa's feelings and kiss multiple women, you'd have to unecessarily trample all over Tifa and her feelings. Hell you'd have brought back Zack to essentially watch as Aerith fawns all over Cloud? I just don't see how that is happening.
