I think a lot of people are using Preferred Name where Nickname would work better. Perhaps Nickname could be relabelled "Known As".
Seems to me change #2 is going in the wrong direction. It's turning Preferred Name into an alternative Nickname and removing the use of Preferred Name for better purposes.
I would suggest that Preferred Name should be kept for cases where people don't want their real name generally known, and other cases where the real name is obscure and people are unlikely to be recognised by it, or where the real name is actually a matter of doubt.
The usage would be
-- if Preferred Name is set, then it's always displayed instead of real name (being "preferred")
-- in the longest formats, eg profile header, you would see "Preferred Name (Proper First Name Middle Names) CLN", subject to privacy, i.e White or Green or TL member.
With people who use their middle names, I guess there are two cases -
-- people who use their middle name informally but would use their proper first name on official forms (should probably use Nickname)
-- people who would appear by their middle name even in records (should use Preferred Name).
The general effect would be that people would normally appear on WikiTree by the name by which they normally appear in records.
The effect of change #2 seems to be that, where people are generally known by a name that isn't their "proper" name, WikiTree will insist on using their "proper" name, however obscure. And there won't be any cure, because setting a Preferred Name won't have the expected effect.
For instance, in the case of the Empress Maud, setting
Proper First Name: Adelaide
Preferred Name : Maud
should do the right thing and make everybody happy, but the effect of change #2 is to do exactly the wrong thing and ensure that the ping-pong continues. Hello Empress Adelaide. Not more compatible with other sites.