That would make for a really really long game. Of all the things you point out, some I agree with some not so much, Eredin and the Aen Elle should have been fleshed out more, iirc, CDPR have admitted as much. As to the white frost, I think they showed too much. Start the epilogue just after Ciri enters the portal, and the "white frost" is left to our imagination, more powerful story telling in my mind.
Hey, I wouldn't mind if the Witcher 3 were longer. 
However I don't think it would have added that much more. I think there could've been a way to add Iorveth or at least have put him in one of the expansions. They wouldn't have even had to make it a long quest with him; I was just shocked that he was missing after having two completely diverging paths during the witcher 2 and I kind of missed him a bit. Witcher 3 has tons of beautiful side quests but I would have sacrificed just a few of them for a little more attention to these other areas. I know it's a hard balance to strike though, so I'm not unreasonable.
I would have just cut the white frost all together and used that time to focus on the wild hunt, maybe a flashback from Geralt or Ciri could have helped, nothing overly large but I can respect that might just be my opinion.
As for Ciri and yen, with just a few extra lines from Ciri referring to yen as her mom then I would have been satisfied; it's just that you see such a close bond with Geralt and Ciri and they don't really show it with her and yen. All in all though, there's far more good then bad and I'm really just being nit picky right now but I'm like this with every game I play.
I am not ashamed to admit I am a Witcher fangirl. TW3 is high, high on my list of greatest games I ever played. That being said, I can see flaws, too. I won't get into them because I have posted before and to be honest, most of my complaints were fixed in patches or DLCs, but I agree with the Shani fans who were disappointed she was glossed over in TW2. I was glad for the Shani fans in HoS, but I also agree with Tommy that it tried to smoosh us with her.
I agree with you that it shouldn't be a war between fans. I can't speak for everyone, but in my case, if I didn't like DA and ME, I wouldn't be here. I have been here since the beginning when it was the old site with Origins. DAI and ME3 have left me sad and worried about future games. When I see games that work and appeal to the elements I want to see in future games, then yes, I do hope Bioware pays attention. I want to play MEA and be able to talk about how awesome that game was. I want to really love the next DA game. I want to be able to feel the same enthusiasm I feel with those games like I feel when I pop in TW3. I understand not everyone is a fan of the Witcher series and would prefer if Bioware stay away from it's template and that's fine. For my part, though? Whether Bioware take notice of CDPR or not, something has to change. It feels to me like they're getting left behind and I don't wish to see that happen.
I agree with you, which is why I'm always curious as to why some people don't take any constructive criticism well; it's constructive, it's meant for future improvement. Witcher 3 is one of my top games and realistically probably as close to perfection as a game can get for me, which was close to how I felt about DA Origins as well. I guess it's just when I think of fanboy or fangirl I immediately think of someone who's blind to a fault which hinders improvement instead of helping but that could just be my interpretation. I mean, the witcher game's made so many improvements on critiques alone that it's unreal and I like how they don't overdo it either, which is something I would like from Bioware in the future; Bioware seems to have a habit of throwing the baby out with the bathwater lately. Anyway, I find your posts waaay too reasonable to be a fangirl but then maybe I should just reconsider my perception of the word. 