Yoshi-P commented on NPC romance in an article recently. You can see his reply here. I've seen people love the idea of NPC romances and others who despise it. I've read a few reasons as to why it's hard to implement, which got me thinking about how something could be done to address those issues.
So if they ultimately can't do NPC romance, maybe they should do NPC buddy quests. I know it sounds redundant since you can say "Just replay the expansion that NPC appears prominently in" but the expansions usually deal with larger-than-life, big world dilemmas rather than anything personal. I'm thinking in the terms of Mass Effect 2 loyalty quests, where the WoL deals with a personal issue of an NPC and in doing so grows closer to that NPC in terms of friendship. It wouldn't be something with nations and countless people at stake, but an issue that is dear to the heart of the NPC.
I mean, in your circle of friends, you are usually closer to one or two of them, right? I think it would add some personal customization for our WoLs to have the ability to choose our BFFs. Although it's kind of a moot point if you can do all the friendship quests, it'll probably be best to limit the ability of how many you can do, so like 3 or so NPCs you can be buddy-buddy with.
I might add that these friendship quests can be used as a good foundation or pre-requests if they ever do implement NPC romance. Or if they never do, at least we would have the buddy quests. They could load the quests with innuendo and ambiguous lines that can be interrupted either way to satisfy those who want a romance if they never implement it. And, like Yoshi-P said, if our buddy Urianger wants to go to Mars, that's okay, we can have a throwaway/optional nonspoken line that we're sad to see him go and hope he comes back soon cause he's our bro.
I might add that these friendship quests can deal with something personal about the WoL too and our buddy coming to our aid (thus have our friendship be a two-way street). Of course, it would have to be a broad issue like you're helping Aymeric with something personal and suddenly someone says, you, as the Fortemps ward, owe millions of gil in back taxes or something, and Aymeric uses his power to just handwave it all away for you...this is a bad example, of course, but I hope it gets the point across.
The whole thing boils down to that we get to spend more time with our favs and our WoLs get to have a little bit of customization in terms of who our closest buddies are but it doesn't pigeonhole the NPCs in a way they couldn't be dynamically used in the future. It also deals with the idea of having to animate any type of hugs/kisses etc, since as buddy quests, there would be none of that.
I'm sure there are other alternatives to this, but I think it's a good halfway point. What do you think?
EDIT: TL;DR > Let's simply have a PLATONIC questline for NPCs so we can get to know them better, spend more time with them PLATONICALLY, and be better buddies with them.