There are a lot of good arguments for both sides in this thread.
In my view in a tabletop setting you have your DM so ignoring alignment is easy and they can just tell you if your paladin screwed up too much and has fallen or if massacring that kobold tribe was for the greater good to protect the town and thus a good act or if it was just killing for killings sake and evil. This being a video game we don't have that luxury. We are going to have a list of specific dialog options to choose from rather than being able to say or do whatever we can think of.
While I am for having alignment I understand why people wouldn't want it. I remember playing Pathfinder Kingmaker (A great game) and having issues stuggling to stay Lawful Good, having to pick dialog options I didn't want to in order to keep my alignment. Thats not good. I also don't think alignment should be a restriction to your actions, but rather a general representation of you behavior. Let evil characters do good things that move them towards being good and let good characters do evil things that cause them to become evil but never say "Your character can't do such and such because they are good/neutral/evil". This results in a lot of chaotic neutral charcters that do things just because.
How I would work it is having something like an "intent" setting as something you select or possible tied to your class or personalality traits, ideals, bonds or flaws (which are all part of making a character in 5th ed). This way you could keep all the dialog options the same for the most part but be able to assign a different point value to your choices depending on your "intent" setting or other circumstances. So for example an Oath of the Ancients Paladin might go 3 points towards evil for massacring a tribe as its tenants align with mercy and forgiveness where as an Oath of Vengeance Palading might not change at all because one of their tenants is fight the greater evil.
Unfortunately nothing is going to be perfect with the lack of a DM but I can't think of a better way mechanically to implement stuff like a paladin falling or a hero giving in becomming corrupted by the promise of power or a cutthroat brigand redeeming himself and becoming part of the good fight. I also understand with this being so complicated why they would choose to omit alignment altogether and I wouldn't hold it against them (Even if its WotC decision or not). I think if it was done right it could add a lot though.
