[SPOILERS]Considering that new Minfilia feature.

[Vidu]

Okay, its even better then. How nice that Thancred failed her again, now letting her die for good. What a "great" outcome. But of course, its not him who failed her this time, it was her decision to willingly give up on her life and make that new and loved by all Ryne live. Embarassing. I just cant say enough how disappointed I am with how they handled Minfilia, never giving her a chance to redeem herself, never giving her a chance to actually live with this "one must absorb another" bullcrap.

And sure, if you are so determined in not accepting that his feelings were romantic -- fine but it doesnt matter what feelings he had, he wished for her to live, to be able to see her again and make up for his fails. It was all in that flashback. You can say he didnt have any romantic feelings with which I can argue but he felt something. Something that even made him rush all the way to save Ryne and I believe the true reason why he did (I think he just wanted it to look this way that he saved her because he didnt want her to be trapped) it is because he hoped that Ryne would resemble his Minfilia or at least someday his Minfilia will wake up in her. And she did for a mere minute. Straight after she went to slumber in Ryne again, Thancred emotionally distanced himself from her, meaning that he didnt really cared about her at all, only wanted his Minfilia to wake up in her.

Which brings us to bad character development. Thancred reaction after Ryne obtained Oracle powers looked like they want to patch holes. Why would he be so nice to Ryne when she was a reason why one he wanted to protect so much died? It was not convincing at all seeing him being so nice to Ryne when he was so butthurt thoughout all story and now boom, he suddenly becomes the best dad ever? How cheap.

And how cheap it was to not even giving old Minfilia a chance. Of course with all the unjustified hate shes been getting and how she lost all value to the plot they would want to get rid of this character. And you can even say that they chose the most "painless" variant. But they just want you to think like it. They introduced a new Minfilia, a cute child with whom you just cant not fall in love with, told us a story about all previous Minfilias that gave up their life fighting for this world, gave her a will to live and make this world a better place, even made her damsel in distress, made us care and feel for her -- and then made us think that old and hated Minfilia giving up her life so that Ryne can live and save this world is a right thing to do. But they only want you to think like it. And judging by this thread, they succeeded pretty well.

To me your reasoning still sounds as if you're extremly set on this whole "Thancred and Minfilia could become the greatest couple in Eorzean history"-path that just doesnt hold up.

Since I only have limited time right now, I only want to tackle a few points:
1) Of course he felt something for Minfilia - it just wasnt romantic. Its kinda fitting that a few of the Shadowbringers bosses are named for different concepts of love - you might want to read up on that! But not all love is "Eros", "Philia" and "Storge" are some form of love too. And I dare say that all Scions wished for their friend Minfilia to live, but for the others it was easier to accept that she is now gone because they werent like a parent to her nor did they kill her father and failed to be a good step-dad to her.
2) Honestly, I'm not even sure if Thancred is supposed to be the "boyfriend/husband"-type. Hes a womanizer in the end - in Shadowbringers end aswell, considering how he (or Urianger?) mentions something about some girls he went out to drinks with. BUT hes trying to be a father-figure and since he failed in that regard with Minfilia, he can consider Ryne a new chance now - to make up for hes failure with Minfilia and to show that hes grown and learned from his mistake. Hes now ready to take care of someone and that someone is Ryne.
And maybe he only took her in at first because he was hoping to get Minfilia back, but that doesnt mean that his reason cant change and he cant become to actually like Ryne for herself - as a "daughter", not a girlfriend!

Personally I dont understand why you wanted them to work on old Minfilia so badly - they would have had to re-write that character completly to make her into an actual character - yes, I'm one of those people who never liked her, because she was nothing more than eye candy to me and not a candy I enjoyed, so to speak. Just letting her die for good was the right way to go. Seriously, even if she had absorbed Ryne, do you believe she and Thancred could have become a couple? After she was basically part of a primal thats supposed to be the Will of The Planet for we-dont-even-actually-know-how-long? After all that she must have seen and done? After all the lifes she has lived - and ended because of that, all the Rynes before the Ryne we have now?
To me this wasnt a cheap way out - it was mercy, for Minfilia, for Ryne and for those of us who rejoyced after seeing her gone in Heavensward.
I personally dont like Ryne either, but at least she isnt just eye candy, she actually does things, has a will of ehr own (now) and might grow into a real character. Something Minfilia couldnt achieve anymore - at least not without making a 180° turn with her character.

We had the same with Yda, kinda: As most of the old Scions she was a pretty bad character, as in: not having a real or intresting personality. So she was replaced with Lyse, a blank slade - instead of needing to come up with a convulted reason why she suddelny has a character.