No Changing Hair Styles/Beards After the Start of the Game. Why BioWare?

I'd say gameplay is necessary in a game? I understand your point, but games have a limited budget and a very stringent schedule. BioWare cannot do anything and everything. They have priorities. They have a list of things going in and things being cut. It's the dirty, ugly business of how games are made and this feature you want is just never a huge priority.

Geralt would have to trim his beard on occasion and there were a few hairstyle options at barber shops, but I'd hardly call that substantial or game-changing. Mass Effect 1 didn't have any sort of character creator available in the game after creating your Shepard, so I'm not really sure what you are getting at. Horizon: Zero Dawn is not even an RPG and has a fixed protagonist you can't customize at all to my knowledge.

Perhaps you just skipped the codex in ME3, but there was plenty of love and labor put into that game. Considering BioWare had less than two years to develop and ship the game, it's honestly amazing what they were able to do in such a short amount of time, and I'm not even including the introduction of a multiplayer feature.

I guess my issue with your post is "the little details" is so subjective, broad, and ambiguous that it's too unwieldy to try and justify in a discussion. There might not be "little details" you like in these games, but I'm certain there are little details others like that you merely gloss over.

Mass Effect 1 was a great game, but the gameplay was absolutely horrific. I've never heard of a third person shooter where you can't even aim. Not to mention, there was no body part hit detection and the entire experience was just holding down a trigger and pointing at sponge enemies. I enjoyed some aspects of the RPG progression (although a war hero having to learn how to aim with a sniper was hilarious), but a lot of the gameplay in ME1 was unpolished and quite frankly a mess.

Mass Effect 2 took that gameplay and made it fun. Was a lot removed? Absolutely. Did BioWare have a lot of time to make the game? Not at all. They did the best they could with the limited time they had and ME2 and ME3 are respectable games. MEA is an attempt at taking that refined gameplay of ME2/ME3 and regaining some of the depth ME1 had.

Reasonable minds may differ, but I find this rather low priority compared to the other systems and features that absolutely should be in the game.