At the bottom of the "Achievements" dropdown, there is a new section displaying the next privilege & badge, similar to the profile page ones:
It's nice, but for experienced users I don't really see it being that useful, as it adds clutter to an already packed UI, and hides information which I do want to see, forcing me to scroll. Especially on Meta sites, the information it shows may not be very useful for me:
In some cases it may even be bad: reminding me that I only have to upvote 14 more things in order to get the electorate badge, and new or badge-hungry users may go and upvote something just to get the badge. (I believe this has been discussed before, but seeing the "reminder" every time you open the achievements dropdown would make this worse.)
Also, as mentioned in the answer, if it's showing a gold badge, it draws your attention even if you're not directly looking at it, thus being somewhat distracting.
Is it really necessary? - Looks like feature creep to me.
Could we get an option to disable this? - I know I could write a userscript of some kind, but still.