Valentine's Day Sanvers Episode in the Plans, Might Be Detrimental?

In essence I agree with the premise you've put forth but will withhold judgement until such an episode is aired.

Let's keep an open mind on how the relationship plays out before jumping to any rash conclusions. The final on-screen proof might be positive or it might backfire. Ultimately, it's a matter of wait-and-see.

Having said that, I wouldn't mind if they (the writers and the EP's) toned the Sanvers relationship down a notch or two since the acceptance point has already been made.

Just a little something extra, our spoiler page has more info on this episode. Readers beware!

I read on I think EW that Maggie is not that keen on Valentine's Day. In honest reality, neither am I. But, I wish Supergirl and Alex were my valentines.

I wouldn't mind if they (the writers and the EP's) toned the Sanvers relationship down a notch or two since the acceptance point has already been made.

Rom I am in agreement with you. Besides it could distract from their jobs, Sanvers I mean.

"Alex has the narrative role of badasss agent + loving sister,.."
If the show were to restrict Alex to this narrow role she would get boring very quickly. Alex not having a life becides bring a DEO agent and Kara's sister is sorta like not seeing Superman in season 1. It worked well in the first season but couldn't continue if the show was to move forward with Kara's journey. Alex would've become a two dimensional cliche. I think that's part of what's wrong with James, everyone else around him was changed by the events of last season and he's been left behind. If Kara is going to grow then her relationship with Alex can't stay exactly the same as it was last season. Essentially Alex evolving by having a life allows Kara to do the same while still allowing the sisters to remain close. It would also be criminal to have an actor as talented as Cryler Leigh and restricted her to a narrow role.

"...Have those two happy ever after and then simply treat their love as the norm. No more bumps and no more narrative arcs about it."
I'd be very disappointed in the writing if there weren't anymore bumps. This show portrays the most realistic sibling relationship currently on TV (arguably ever on TV) and what makes it realistic is the bumps. Kara and Alex, who would literally die for each other, don't simply have a "happy ever after" so it wouldn't fit for Alex and Maggie to just have a problem free everything's great relationship. In real life every relationship no matter what type takes work.

That being said I don't want Alex and Maggie to have to work too hard. I would be happy for a stretch of episodes where they're in a problem free zone. I can see a situation where Alex and Maggie make V-Day plans that are "ruined" by the villain. That's not a relationship issue just the the lives of a DEO agent and Cop.

With complete respect to your own opinion and viewing standards, I'd like to comment on a few points. Don't have to agree with me.

Narrative role has little to do with talent. Melissa Benoist is a beast, yet Kara has a narrative role. Day job, interaction with friends and Supergirl. We wouldn't see Kara starting to punish criminals arrow style or or suddenly become the permanent antagonist. Kara's personality and mood sometimes alters, such as Red Kryptonite or Dominator control, and that allows MB to express a wide range, but her narrative role isn't betrayed and those things are temporary. Winn has been the tech guy and always will be the tech guy. Plenty could be done with him like in Supergirl Lives but he's still in that role. We have ONE EXAMPLE of a character that shifts out of narrative roles, and that is infamous James/Guardian. His uncertain plot role shifting from friend to lover to friend to boss to vigilante contributes to why the character is currently so unenjoyable.

A realistic relationship isn't perfect, but people don't fly and shoot lasers from eyes either. If the show was about Alex, then by all means make the romance as detailed as possible (although the Olicity business on Arrow has shown even when it's about the main character, a fluctuated romance overdone is not fun to watch at all). However the show is not about Alex. Alex is a supporting character, a beloved one but still so. Winn's brief romance with Siobhan was an example of what a supporting character relationship might look like, and Alex's has already far surpassed that. No complaints about its current length, as this one also needed to make a statement about being lesbian, and it was so excellently done, but past that it's an arc like any other. Never has the love lives of Cisco Ramon, Caitlin Snow, Wally West, John Diggle etc substituted screentime of Barry Allen and Oliver Queen. What has occured with Alex is beautiful, but it cannot be a focus of the show any longer. Kara's own love life is portrayed as much as she was involved in the "4 show crossover" (i.e not much at all).

Revised opinion after reading the spoilers page: I still reckon they shouldn't drag this on but as a thematic Valentine's episode the premise is not bad